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           TATAYANA OSBORN ET AL. v. CITY
               OF WATERBURY ET AL.
                     (SC 20129)
             Robinson, C. J., and Palmer, McDonald, D’Auria,
                      Mullins, Kahn and Ecker, Js.

                                  Syllabus

The plaintiff mother and her minor child, T, an elementary school student,
   sought to recover damages from the defendant city of Waterbury and
   the defendant Waterbury Board of Education for injuries that T sustained
   when she was physically assaulted by two or more schoolchildren on
   a Waterbury public school playground during recess. The plaintiffs
   alleged, inter alia, that the defendants and their employees failed to
   adequately supervise the schoolchildren, including T, both in and out
   of the classroom. The case was tried to the court, which found that T’s
   injuries were the result of the defendants’ failure to provide sufficient
   personnel to exercise proper control over the number of students on
   the playground at the time. There was evidence introduced at trial that
   the school had a student population of about 400 and that at least 2
   paraprofessionals who attended the incident involving T ran from inside
   the building to address the situation. The defendants appealed to the
   Appellate Court from the judgment in favor of the plaintiffs, claiming
   that the trial court improperly rejected the defendants’ special defense
   of governmental immunity, incorrectly concluded that T’s injuries were
   caused when an inadequate number of staff members were assigned to
   supervise up to 400 students when there was evidence that there were
   no more than 50 students on the playground at the time in question,
   improperly found, in the absence of expert testimony, that the number
   of assigned staff members was insufficient to control as many as 400
   students, and improperly awarded certain damages. The Appellate Court
   concluded that, in the absence of expert testimony, the trial court could
   not properly have found that the defendants breached their duty of care
   to T on the basis that there was an allegedly inadequate number of
   adults on the playground to supervise the students. Accordingly, the
   Appellate Court reversed the trial court’s judgment and remanded the
   case to that court with direction to render judgment for the defendants.
   The Appellate Court did not reach any of the defendants’ other claims.
   On the granting of certification, the plaintiffs appealed to this court.
   Held that, under the facts of the present case, expert testimony was
   not required to establish the plaintiffs’ claim of inadequate supervision,
   and, because the Appellate Court incorrectly concluded that the trial
   court could not determine that the defendants breached their duty of
   care to T without such testimony, the judgment of the Appellate Court
   was reversed and the case was remanded to that court for consideration
   of the remaining issues on appeal: although the education profession
   is a highly regulated field, the fact finder was required to determine
   only whether there was adequate supervision of children under the
   circumstances of the case, a task that was within the common knowledge
   of a layperson and that did not require the fact finder to apply scientific
   or specialized knowledge; moreover, even if there had been expert
   testimony regarding the desired ratio of staff to children and the facts
   demonstrated that the school met that ratio, the fact finder still could
   have determined that the supervision was inadequate because adequacy
   was not based simply on numbers, and nothing in the complaint limited
   the plaintiffs’ inadequate supervision claim to a mere numerical calcula-
   tion between the number of students and the number of adults.
                (Three justices dissenting in one opinion)
         Argued March 27—officially released December 3, 2019

                            Procedural History

   Action to recover damages for personal injuries sus-
tained by the named plaintiff as a result of the defen-
dants’ alleged negligence, and for other relief, brought
to the Superior Court in the judicial district of Water-
bury, where the action was withdrawn as to the defen-
dant Stephanie Pascale et al.; thereafter, the case was
tried to the court, Hon. Barbara J. Sheedy, judge trial
referee, who, exercising the powers of the Superior
Court, rendered judgment for the plaintiffs, from which
the named defendant et al. appealed to the Appellate
Court, Lavine, Prescott and Harper, Js., which reversed
the trial court’s judgment and remanded the case with
direction to render judgment for the named defendant
et al., and the plaintiffs, on the granting of certification,
appealed to this court. Reversed; further proceedings.
  Richard M. Franchi, for the appellants (plaintiffs).
  Daniel J. Foster, acting assistant corporation coun-
sel, for the appellees (named defendant et al.).
                         Opinion

   MULLINS, J. This appeal arises from an action filed
by the plaintiffs, Tatayana Osborn (child), a minor child,
by and through her mother, Tacarra Smith, alleging
negligence on the part of the defendant city of Water-
bury (city) and the defendant Waterbury Board of Edu-
cation (board) for injuries sustained by the child during
an altercation with other students during recess at a
Waterbury public school.1 In this certified appeal,2 we
must determine whether the Appellate Court correctly
concluded that expert testimony was necessary to
establish the standard of care in this negligence action.
We conclude that, under the facts of the present case,
expert testimony was not necessary. Accordingly, we
reverse the Appellate Court’s judgment and remand the
case to that court for consideration of the remaining
issues on appeal.
   The opinion of the Appellate Court, as supplemented
by the record, sets forth the following facts and proce-
dural history. ‘‘On April 25, 2012, the child was an ele-
mentary school student when she was assaulted by
other students while they were on the playground dur-
ing the lunchtime recess. As a result of the assault, the
child sustained a cut to her face that required sutures
. . . and [that] resulted in scarring. The plaintiffs com-
menced the present action against the city [and] the
board, [among others].’’ Osborn v. Waterbury, 181
Conn. App. 239, 241–42, 185 A.3d 675 (2018). In their
complaint, the plaintiffs alleged, inter alia, that the
plaintiffs’ injuries and damages ‘‘were caused by the
negligence and carelessness of the defendant[s] in that
[they] . . . failed to adequately supervise the children
both in and out of the classroom, including the [child].’’
   ‘‘The parties tried the case to the court. Following
the presentation of evidence, the court issued a memo-
randum of decision in which it found that the child was
a fifth grade student at Sprague Elementary School in
Waterbury when she was assaulted by two or more
students on the playground. The playground was sur-
rounded by brick walls and fencing, and, following
lunch, students occupied the area for play and exercise.
More specifically, the child was surrounded by a circle
of students who physically assaulted her and pushed
her into a stone wall, causing injuries to her nose and
cheek with resulting facial scarring. The child experi-
enced posttraumatic headaches for a sustained period
of time, but the most serious effect of this schoolyard
assault was its lingering effect on the child’s emerging
personality and self-image.
  ‘‘The court also found that Danielle Avalos, a school
paraprofessional, was assigned to monitor the students
on the playground during recess. She was not provided
with written documents that listed her duties during
the lunchtime recess. Her two day professional develop-
ment training occurred prior to the first day of school
and focused on the forms of student bullying and the
need to distinguish between bullying and students
merely ‘picking on’ other students or otherwise being
unkind to them.’’ Osborn v. Waterbury, supra, 181 Conn.
App. 242–43.
   The trial court found that ‘‘[t]here was also no evi-
dence to suggest that only portions of the student body
were released for [lunch] at a given time; it is more
likely the student body ate together in the [lunch] room
and then went outside for recreation—in large num-
bers.’’ The trial court further found that, ‘‘[a]t the time
of the incident, classroom teachers were on [lunch]
recess (and there was no evidence to establish that
staff lunch times were staggered). The court concludes
that 1 student intern and 3 or 4 staff members were
not sufficient to exercise control over as many as 400
students [on the playground].’’
  ‘‘With respect to the incident during which the child
was injured, the court found that Avalos saw a student
repeatedly punch the child in the face and push her
into a wall. A precis prepared by the nursing division of
the Waterbury Health Department referenced, ‘a large,
deep cut on the [child’s] left cheek’ and ‘a cut of lesser
depth on the bridge of her nose.’ ’’ Osborn v. Waterbury,
supra, 181 Conn. App. 243–44. The court rendered judg-
ment in favor of the plaintiffs.
  After trial, the defendants sought an articulation from
the trial court pursuant to Practice Book §§ 61-10 and
66-5. Specifically, the defendants requested that the trial
court articulate ‘‘(1) whether the court found either or
both of the individual defendants who remain in the
case to be liable for the plaintiffs’ injuries and losses,
and, if so, on what basis, and (2) whether the court
found that the plaintiffs’ injuries and losses were caused
by the fact, as found by the court, that the number of
adults present on the playground where the injuries
took place was insufficient to exercise proper control
over the number of students present.’’
  The trial court responded to the defendants’ request
for articulation as follows:
  (1) ‘‘This court did not find any remaining individual
(specifically . . . Avalos or Donna Perreault) was lia-
ble for the plaintiffs’ injuries or losses . . . .
  (2) ‘‘This court found [that] the injuries and/or losses
were as a result of the [city’s] failure to exercise proper
control over the number of students present.
   (3) ‘‘The court (in [an] August 12, 2016 ruling) found
[that] the plaintiffs’ injuries were caused by insufficient
staffing of personnel to exercise proper control over
the number of students on the playground at the time
(perhaps as many as 400 students) . . . .
  (4) ‘‘The court concluded [that] the injuries to the
plaintiffs were proximately caused by an insufficient
number of staff personnel—to monitor the actions of
students on the playground on the date of injury.’’ (Cita-
tion omitted; emphasis in original.)
   The defendants appealed from the judgment of the
trial court to the Appellate Court, claiming that ‘‘the
trial court improperly (1) rejected their special defense
of governmental immunity for discretionary acts, (2)
concluded that the plaintiffs’ injuries were caused when
an inadequate number of adults were assigned to super-
vise up to 400 students when there was evidence that
there were no more than 50 students on the playground,
(3) found in the absence of expert testimony that 1
student intern and 3 or 4 staff members were insuffi-
cient to control as many as 400 students on the play-
ground, and (4) awarded damages intended to encour-
age continued therapy and occupational training for the
child in the absence of evidence that she would need
such services in the future.’’ Osborn v. Waterbury,
supra, 181 Conn. App. 241.
  The Appellate Court concluded, ‘‘as a matter of law,
that without expert testimony, the court could not prop-
erly have found that the defendants breached their duty
of care to the child [on the basis that] there was an
inadequate number of adults on the playground to
supervise the students at the time the child was injured.’’
Id. As a result, the Appellate Court reversed the judg-
ment of the trial court and remanded the case with
direction to render judgment for the defendants. Id.,
247. The Appellate Court did not reach any of the defen-
dants’ other claims on appeal. This certified appeal
followed.
  On appeal to this court, the plaintiffs assert that the
Appellate Court incorrectly concluded that, without
expert testimony, the trial court could not determine
that the defendants breached their duty of care to the
child. The defendants respond that the Appellate Court
correctly determined that expert testimony was neces-
sary to establish the standard of care. We agree with the
plaintiffs that the Appellate Court incorrectly concluded
that the trial court could not determine that the defen-
dants breached their duty of care to the child without
expert testimony.
   Before we begin our analysis, it is important to clarify
two points. First, we read the plaintiff’s complaint and
the trial court’s ruling thereon to involve a claim of
inadequate supervision. Unlike the defendants and the
Appellate Court, we understand the trial court’s
response to the request for articulation, namely, that
‘‘the injuries and/or losses were as a result of the [city’s]
failure to exercise proper control over the number of
students present,’’ as a conclusion that there was inade-
quate supervision, not that there was solely an inade-
quate number of staff on the playground.3 Such a conclu-
sion is consistent with the well established principle
that ‘‘we read the record in the light most favorable to
sustaining the trial court’s judgment.’’ Weiss v. Smul-
ders, 313 Conn. 227, 232 n.2, 96 A.3d 1175 (2014). As
a result, we consider whether expert testimony was
required for the plaintiffs’ negligence claim of inade-
quate supervision.4
   Second, we understand that the linchpin of the Appel-
late Court’s decision is that, because schools are highly
regulated areas, expert testimony was required. We dis-
agree that the fact that a particular area is highly regu-
lated necessarily means that expert testimony is
required for claims of negligence arising in that area.
Rather, we conclude that, irrespective of the heightened
regulations of a particular field, whether expert testi-
mony is required to support a claim of negligence turns
on whether the alleged claim of error is within the
common knowledge of a layperson.5
   ‘‘As an initial matter, we note that the [trial] court’s
determination of whether expert testimony was needed
to support the plaintiff’s claim of negligence against the
defendant was a legal determination, and, thus, our
review is plenary.’’ (Internal quotation marks omitted.)
Doe v. Hartford Roman Catholic Diocesan Corp., 317
Conn. 357, 373, 119 A.3d 462 (2015).
   ‘‘The essential elements of a cause of action in negli-
gence are well established: duty; breach of that duty;
causation; and actual injury. . . . Contained within the
first element, duty, there are two distinct considera-
tions. . . . First, it is necessary to determine the exis-
tence of a duty, and [second], if one is found, it is
necessary to evaluate the scope of that duty. . . . We
sometimes refer to the scope of that duty as the requisite
standard of care. . . .
   ‘‘[O]ur threshold inquiry has always been whether the
specific harm alleged by the plaintiff was foreseeable
to the defendant. . . . By that is not meant that one
charged with negligence must be found actually to have
foreseen the probability of harm or that the particular
injury which resulted was foreseeable, but the test is,
would the ordinary [person] in the defendant’s position,
knowing what he knew or should have known, antici-
pate that harm of the general nature of that suffered
was likely to result? . . . The idea of risk in this context
necessarily involves a recognizable danger, based upon
some knowledge of the existing facts, and some reason-
able belief that harm may possibly follow. . . . Accord-
ingly, the fact finder must consider whether the defen-
dant knew, or should have known, that the situation at
hand would obviously and naturally, even though not
necessarily, expose [the plaintiff] to probable injury
unless preventive measures were taken.’’ (Citations
omitted; internal quotation marks omitted.) LePage v.
Horne, 262 Conn. 116, 123–24, 809 A.2d 505 (2002).
  ‘‘[E]xpert testimony . . . serves to assist lay people,
such as members of the jury and the presiding judge,
to understand the applicable standard of care and to
evaluate the defendant’s actions in light of that stan-
dard. . . . Expert testimony is required when the ques-
tion involved goes beyond the field of the ordinary
knowledge and experience of judges or jurors.’’ (Cita-
tion omitted; emphasis omitted; internal quotation
marks omitted.) Id., 125; see Doe v. Hartford Roman
Catholic Diocesan Corp., supra, 317 Conn. 374; see also
Doe v. Yale University, 252 Conn. 641, 686–87, 748 A.2d
834 (2000) (‘‘[w]hether expert testimony was required
to support the plaintiff’s claim compels us to consider
whether the determination of the standard of care
requires knowledge that is beyond the experience of
[the] fact finder’’ [internal quotation marks omitted]).
Indeed, this court has often said that ‘‘[t]he trier of fact
need not close its eyes to matters of common knowl-
edge solely because the evidence includes no expert
testimony on those matters.’’ Way v. Pavent, 179 Conn.
377, 380, 426 A.2d 780 (1979); see also Doe v. Hartford
Roman Catholic Diocesan Corp., supra, 375 (‘‘[j]urors
are not expected to lay aside matters of common knowl-
edge or their own observation and experience of the
affairs of life, but, on the contrary, to apply them to
the evidence or facts in hand, to the end that their
action may be intelligent and their conclusions correct’’
[internal quotation marks omitted]).
  Typical cases in which expert testimony is required
are those that ‘‘are akin to allegations of professional
negligence or malpractice . . . .’’ Santopietro v. New
Haven, 239 Conn. 207, 226, 682 A.2d 106 (1996). Never-
theless, expert testimony is not required for all claims
arising from a professional relationship despite the fact
that those areas are highly specialized and regulated.
   There are two types of cases arising from a profes-
sional relationship in which expert testimony is not
required. In one type of case, expert testimony is not
required because the negligence is so gross as to be
clear to a layperson. See Davis v. Margolis, 215 Conn.
408, 416 n.6, 576 A.2d 489 (1990) (expert testimony is
not required in legal malpractice cases ‘‘where there is
present such an obvious and gross want of care and skill
that the neglect is clear even to a layperson’’ [internal
quotation marks omitted]). In the other type of case,
expert testimony is not required because the alleged
claim of error involves a task that is within the common
knowledge of a layperson. See Doe v. Cochran, 332
Conn. 325, 337, 210 A.3d 469 (2019) (explaining that
expert testimony was not necessary because ‘‘alleged
error [was] not one involving professional medical judg-
ment or skill’’). The present case falls within the sec-
ond category.
  Indeed, Badrigian v. Elmcrest Psychiatric Institute,
Inc., 6 Conn. App. 383, 505 A.2d 741 (1986), highlights
this second category of cases. The Appellate Court con-
cluded that expert evidence was not necessary in a
negligence claim against a psychiatric hospital, when
that claim alleged that the hospital failed to supervise
its patients, particularly in crossing a state highway.
Id., 385. The Appellate Court explained that ‘‘[t]he
defendant is attempting to transform this case from one
of simple negligence into that of medical malpractice
requiring expert medical testimony to prove a medical
standard of care and a breach thereof.’’ Id., 386. The
Appellate Court further explained that ‘‘one need not
be guided by medical experts in determining whether
a mentally ill person should be allowed to cross on
foot a heavily traveled four lane state highway without
supervision. There was no esoteric or uniquely medical
issue to be determined under the allegations of [the]
case, and the court correctly categorized the negligence
charged against the hospital as involving ‘no materia
medica, nor any complex issue requiring specialized
knowledge.’ ’’ Id., 387.
   Similarly, in Cammarota v. Guerrera, 148 Conn. App.
743, 751–52, 87 A.3d 1134, cert. denied, 311 Conn. 944,
90 A.3d 975 (2014), the Appellate Court concluded that
expert testimony was not necessary in a case involving
a claim of legal malpractice. The claim of legal malprac-
tice centered on the defendant lawyer’s act of giving a
check payable to his client to another individual, not-
withstanding the fact that the defendant had been
warned that that individual was untrustworthy. Id., 751
and n.6. The Appellate Court explained that ‘‘[t]he ques-
tion of whether expert testimony is required is not
resolved by characterizing the case as sounding in legal
malpractice or ordinary negligence, but rather by
determining whether the issue, unaided by expert testi-
mony, is within the realm of a jury’s ordinary knowl-
edge. Thus, professional negligence claims do not nec-
essarily require expert testimony, and claims of
ordinary negligence may require expert testimony. The
appropriate question is whether the issue can be reliably
decided by a jury without the assistance of expert testi-
mony.’’ Id., 751.
   In the present case, the Appellate Court concluded
that, ‘‘as a matter of law . . . the standard of care
regarding the number of supervisors needed to ensure
the safety of elementary school students on a play-
ground is not a matter of common knowledge; far from
it. The policies and procedures of our public school
system are highly regulated by governing bodies and
accreditation organizations. School teachers and
administrators are required to be accredited in accor-
dance with educational standards.’’6 Osborn v. Water-
bury, supra, 181 Conn. App. 246. Although we agree
with the Appellate Court that the education profession
is a highly regulated field, our case law demonstrates
the fact that a profession that is highly regulated does
not mean that expert testimony is always required in
cases alleging negligence against a professional in that
field. Instead, whether expert testimony is required in
a particular case depends on whether the alleged error
is within the common knowledge of a layperson.
   In this case, the plaintiffs claimed, inter alia, that
their injuries and damages were caused by ‘‘the negli-
gence and carelessness’’ of the defendants in that they
‘‘failed to adequately supervise the children both in
and out of the classroom, including the [child] . . . .’’
Therefore, we must determine whether the alleged error
here, namely, the supervision of children, involves pro-
fessional judgment or skill, or whether it is a task com-
parable to those that laypeople routinely perform.
   We find this court’s recent decision in Doe v. Cochran,
supra, 332 Conn. 325, instructive. In Doe, we addressed
a claim against a physician for incorrectly reporting the
results of a test for sexually transmitted diseases to a
patient. Id., 329. In concluding that the plaintiff had
alleged a claim of ordinary negligence, we explained
that ‘‘the alleged error is not one involving professional
medical judgment or skill. If the defendant misread [the
patient’s] lab result, then he failed to perform what was,
in essence, a simple, ministerial task. The index to the
report states that a result greater than 1.1 indicates a
positive test, and the report states that [the patient’s]
result was 4.43. No advanced medical training was nec-
essary to determine that [the patient] had tested positive
for herpes; elementary reading and arithmetic skills
should have been sufficient. Indeed, laypeople routinely
perform comparable tasks, such as reading and inter-
preting meat thermometers, oil dipsticks, pool and spa
test strips, and insulin tests.’’ Id., 336–37.
   This court further explained that, ‘‘[o]f course, the
same conclusion holds to an even greater extent if the
genesis of the error was that the defendant simply told
his staff member the wrong test result or the staff mem-
ber relayed the wrong result to [the patient]. That sort
of careless miscommunication could occur in any set-
ting and has nothing to do with the exercise of profes-
sional medical judgment or skill.’’ Id., 337. ‘‘[R]egardless
of whether the alleged error arose from a misreading
or a miscommunication, proving that it constituted neg-
ligence would not require expert medical testimony or
the establishment of a professional standard of care. A
jury will not need expert testimony to determine
whether the defendant’s staff was negligent in leading
[the patient] to believe that he was free of [sexually
transmitted diseases] when the defendant knew, or
should have known, that [the patient] had tested posi-
tive for herpes, a contagious [sexually transmitted dis-
ease], and intended to engage in sexual activity. Such a
determination is well within the ken of a layperson.’’ Id.
  Like the alleged claim of error in Doe v. Cochran,
supra, 332 Conn. 336–37, the task of supervising chil-
dren is one that laypeople routinely perform. It was not
an issue that required scientific or specialized knowl-
edge. To the contrary, a determination of adequate
supervision of children is common knowledge, based
on everyday life. The fact that this incident occurred
on a playground during school hours, rather than on
the same playground after school hours, does not
change the fact finder’s ability to determine what consti-
tutes adequate supervision.
   Moreover, we disagree with the Appellate Court that
the plaintiffs’ claim required the fact finder to determine
‘‘the standard of care regarding the number of supervi-
sors needed to ensure the safety of elementary school
students on a playground . . . .’’ Osborn v. Waterbury,
supra, 181 Conn. App. 246. The fact finder was not
asked to determine solely the required ratio of children
to staff members; instead, the question confronting the
fact finder, based on the allegations in the complaint
and the evidence presented at trial, was whether there
was adequate supervision of the children involved in
this particular incident.7 Indeed, even if there had been
expert testimony regarding the desired ratio of staff to
children and the facts demonstrated that the school
met that ratio, the fact finder still may have determined
that the supervision was not adequate because ade-
quacy is not based just on numbers, and nothing in
the complaint limited the plaintiffs’ claim to a mere
numerical calculation between the number of students
and the number of adults. This was an inadequate super-
vision case.8
   The trial court found that ‘‘[a] large group of students
surrounded [the child]. They threw stones at her—most
of which were aimed at her face. . . . It was . . .
Avalos’ testimony that she saw a student repeatedly
punch the [child] in the face and push her into a wall.’’
The trial court further found that, ‘‘[a]t the time of the
incident, classroom teachers were on [lunch] recess
(and there was no evidence to establish that staff lunch
times were staggered).’’ Furthermore, the evidence in
the present case demonstrated that the paraprofession-
als who broke up the incident and attended to the child
after the child was hurt had to run from inside the
building to address the situation.
  Specifically, Avalos testified that she was assigned
to supervise students on the playground during recess
but that she was inside the school building when she
saw the incident and had to run outside to stop the
incident. Although Avalos testified at trial that she saw
other teachers on the playground when she arrived at
the scene of the incident, the defendants did not present
any testimony from those staff members or any other
staff member who was actually on the playground
supervising the children.9 Furthermore, there was no
evidence that any staff member who was allegedly on
the playground responded to the incident.10
  Therefore, the issue in the present case was whether
the supervision of the children was adequate when a
large group of children was able to gather around the
child, throwing stones at her, and with one student
repeatedly punching the child in the face and pushing
her into a wall. We conclude that the fact finder in
the present case did not need to apply scientific or
specialized knowledge to determine whether the defen-
dants adequately supervised the children in the present
case. Accordingly, we conclude that the Appellate Court
improperly reversed the judgment of the trial court on
the ground that, without expert testimony, judgment
could not be rendered for the plaintiffs.
  The judgment of the Appellate Court is reversed and
the case is remanded to that court with direction to
consider the defendants’ remaining claims on appeal.
  In this opinion PALMER, D’AURIA and ECKER, Js.
concurred.
   1
     The plaintiffs also brought this action against Stephanie Pascale, a fifth
grade teacher; Charles Stango, the president of the board; Danielle Avalos,
a paraprofessional at the school; and Donna Perreault, the school principal.
They withdrew the action against Pascale and Stango in the trial court. In
its articulation, the court clarified that it did not find that Avalos and Perre-
ault were liable for the plaintiffs’ injuries. Avalos and Perreault, therefore,
withdrew from the present appeal. In this opinion, we refer to the city and
the board as the defendants.
   2
     We granted the plaintiffs’ petition for certification to appeal, limited to
the following issues: (1) ‘‘In reversing the judgment of the trial court, did
the Appellate Court properly determine that expert testimony was necessary
to establish the standard of care?’’
   (2) ‘‘Did the plaintiffs receive adequate notice of the need for expert
testimony to determine the scope of the duty of care such that a directed
judgment was appropriate in this case?’’ Osborn v. Waterbury, 329 Conn.
901, 184 A.3d 1214 (2018).
   Because we conclude that expert testimony was not necessary in the
present case, we need not address the second certified question.
   3
     In response to the defendants’ request for an articulation, the trial court
also stated that ‘‘[t]he court concluded [that] the injuries to the plaintiffs
were proximately caused by an insufficient number of staff personnel—to
monitor the actions of students on the playground on the date of injury.’’
It was this statement on which the Appellate Court based its analysis.
Nevertheless, a review of the allegations of the plaintiffs’ complaint, the
evidence presented at trial, the transcripts of the trial, and a fair reading
of the memorandum of decision and articulation in the light most favorable
to sustaining the trial court’s judgment demonstrate that the issue for the
trial court to determine was whether the supervision was adequate, not
merely whether the number of staff was sufficient.
   4
     The dissent is premised on an interpretation of the trial court record
with which we fundamentally disagree. The dissent repeatedly asserts that
‘‘the sole basis of the trial court’s conclusion that the defendants’ supervision
of the children was negligent was the supervisor to student ratio . . . .’’
(Emphasis added.) This conclusion ignores the articulation of the trial court
that ‘‘the injuries and/or losses were as a result of the [city’s] failure to
exercise proper control over the number of students present.’’ This articula-
tion makes clear that the supervisor to student ratio was not the sole basis
of the trial court’s conclusion that the defendants were negligent but that,
regardless of the supervisor to student ratio, the defendants did not exercise
proper control over the students.
   5
     The dissent seems to agree that the fact that schools are a highly regulated
area is not dispositive of whether expert testimony was required for this
claim of negligence. Instead, the dissent’s conclusion that expert testimony
was required in this case is premised on the existence of a board policy
regarding a supervisor to student ratio for supervision, about which the
principal testified. Specifically, the dissent asserts that ‘‘[t]he issue presented
in this appeal . . . is whether expert testimony was required to enable the
trier of fact to determine that the defendants’ supervision of the playground
was negligent, notwithstanding the fact that the supervisor to student ratio
complied with or exceeded the goals set forth in the board’s policy.’’ We
disagree with the dissent that, on this record, the trial court had to accept
that any supervisor to student ratio was established merely because the
principal testified that one existed.
   The dissent acknowledges that ‘‘[t]he written policy . . . was not admit-
ted into evidence, and the court made no finding in that regard.’’ Thus, the
principal’s testimony is the only evidence of the existence of the policy and
what the policy contained; that testimony, of course, was subject to the
court’s finding it credible. The fact that the court made no finding regarding
the policy or what it contained demonstrates to us that the court did not
credit the principal’s testimony regarding the policy or the ratio. Because
the court did not credit the principal’s testimony, we conclude that, as
matter of fact, no particular supervisor to student ratio was established
at trial.
   The dissent also ‘‘disagree[s] . . . with the majority’s suggestion that
there was not enough evidence in the record to allow the trial court, as fact
finder, to draw the reasonable inference that the policy testified to by the
principal was one that was in existence and applicable at the time of the
incident.’’ This misconstrues our conclusion. First, it is axiomatic that the
trial court was not required to credit the principal’s testimony regarding
the policy—neither when the policy was established nor what the policy
contained. See, e.g., In re Gabriella A., 319 Conn. 775, 798, 127 A.3d 948,
960 (2015) (it is undisputed that ‘‘the trial court, as the fact finder, was free
to accept or reject portions of [each witness’] testimony’’). Indeed, the
dissent concedes that the trial court made no findings in this regard.
   Second, we agree that there was evidence, if credited, for the court to
make a finding that the policy testified to by the principal was applicable.
However, there is simply nothing in the record to demonstrate that the trial
court did credit the principal’s testimony. Instead, having had that testimony
before it, the trial court did not make a finding regarding the policy or any
ratio it may have contained. Therefore, we will not elevate that testimony
to a factual finding regarding the proper supervisor to student ratio when
the trial court itself did not do so. Rather, on appeal, ‘‘we read the record
in the light most favorable to sustaining the trial court’s judgment.’’ Weiss
v. Smulders, 313 Conn. 227, 232 n.2, 96 A.3d 1175 (2014). Accordingly, the
fact that there was testimony in the record to support a finding that is
contrary to the judgment of the trial court is irrelevant.
   6
     It is important to note that, although the principal testified at trial that
the board had a ‘‘policy’’ of 1 staff member to 125 students, there was no
evidence regarding whether that was a written or verbal policy, whether
the policy even existed at the time of the incident four years prior to trial
or whether it was adopted in response to the incident. Tellingly, no written
policy was ever introduced into evidence.
   Furthermore, and perhaps more important, even if the board had adopted
a written policy prior to the incident that the school should maintain a ratio
of 1 staff member to 125 students, the fact that the school and the board
complied with its own policy is not determinative of whether the school
was negligent in its supervision of the students in the present case. ‘‘This
court has stated that, [a]lthough a violation of an employer’s work rules
can be viewed as evidence of negligence . . . [self-imposed] rules, regula-
tions and policies do not themselves establish the standard of care. . . .The
rule is well established and is consistent with the general principle that the
standard of care in a negligence action is an objective one, determined by
external standards, and not a rule derived from individual practices.’’ (Cita-
tion omitted; internal quotation marks omitted.) Doe v. Saint Francis Hospi-
tal & Medical Center, 309 Conn. 146, 279, 72 A.3d 929 (2013) (Zarella, J.,
dissenting). There was no evidence presented in the present case regarding
any regulation or accreditation standard regarding the supervision of
students.
   7
     In their complaint, the plaintiffs alleged, inter alia, that their ‘‘injuries
and damages were caused by the negligence and carelessness of the defen-
dant[s] in that [they] . . . failed to adequately supervise the children both
in and out of the classroom including the [child] . . . .’’
   At trial, the plaintiffs’ counsel explained as follows: ‘‘A couple of things
we know: even though [Avalos is] on recess duty . . . [s]he wasn’t there
during recess, at least part of it, the part where my client got injured. Also,
there was another person who was supposed to be on duty; her name was
Marlene. She was not on the playground as her recess duty schedule required,
while my client was being assaulted. What we know is they looked out a
window inside the building, at least one of them, and at that point in time
. . . Avalos sees something happening. She then runs through the cafeteria
carrying two walkie-talkies. She gives one to Marlene, goes outside, and
starts running toward some people. Supposedly, Marlene is in back of her;
this is what she says.’’
   8
     The following colloquy between the trial court and the defendants’ coun-
sel demonstrates that the issue before the trial court was whether the
supervision on the playground was adequate, not merely whether the number
of supervisors on the playground was adequate:
   ‘‘The Court: Well, let me ask you another question, Counsel . . . . Do
you claim that, at the time the injury was inflicted upon the [child], there
was anybody providing supervision and guidance on the playground?
   ‘‘[The Defendants’ Counsel]: Yes.
   ‘‘The Court: Who?
   ‘‘[The Defendants’ Counsel]: The paraprofessional . . . Avalos, was at
the door, as well as—
   ‘‘The Court: What door? What door?
   ‘‘[The Defendants’ Counsel]: The door from the cafeteria leading to—
   ‘‘The Court: That’s not where the injury occurred.
   ‘‘[The Defendants’ Counsel]: Well, the injury occurred on the playground.
   ‘‘The Court: Well, yeah, I mean that’s like saying, you know, I live in—
   ‘‘[The Defendants’ Counsel]: Well then, no, Your Honor, then no one was
at the exact scene where this incident occurred.
   ‘‘The Court: Okay.
   ‘‘[The Defendants’ Counsel]: But for—
   ‘‘The Court: And there was nobody on the playground at the time.
   ‘‘[The Defendants’ Counsel]: Well, no, I disagree with that, as well.
There is—
   ‘‘The Court: Well, then tell me who they are so that I can correct that misim-
pression.
   ‘‘[The Defendants’ Counsel]: The gym teacher and—is Ms. Thompson, I
think; and then Ms. Yago (phonetic), who—the health teacher, I believe.
There were two—One was playing kickball and one was walking around.
That was—
   ‘‘The Court: But nobody—nobody was there for the purpose of supervising
the students at—on the playground.
   ‘‘[The Defendants’ Counsel]: The purpose of those individuals being on
the playground is to supervise, as well as to interact with students.
   ‘‘The Court: Oh, so you can supervise and play kickball at the same
time, Counsel?
   ‘‘[The Defendants’ Counsel]: I don’t know if they were supposed to be
playing kickball, per se, but they’re on the playground in order to interact
[with] and supervise the students.’’
   9
     The trial court commented as follows: ‘‘[T]hat’s why I come back again
to who was out there supervising the children. It doesn’t appear clear to
me at all from the evidence that was submitted, and you could have put on
somebody who would have so testified clearly.’’
   10
      In its memorandum of decision, the trial court explained: ‘‘The court
concludes that 1 student intern and 3 or 4 staff members were not sufficient
to exercise control over as many as 400 students [on the playground].’’ It
is important to note that the trial court did not find that 4 teachers and 1
student intern were on the playground. Indeed, the testimony at trial was
not clear on this point. Although Avalos testified at trial that other staff
members were on the playground when she arrived outside to break up the
incident, contradictory testimony from her deposition was also admitted
into evidence. At her deposition, Avalos testified that she did not recall any
other staff members being on the playground when she arrived outside to
break up the incident. This understanding is bolstered by the fact that,
during closing arguments, the trial court remarked as follows: ‘‘The court’s
concern is whether or not there was in fact anyone [on the playground].’’
The court certainly appeared skeptical of the principal’s testimony that four
staff members were on the playground. Indeed, as we have mentioned, the
court pointed out that it did not hear from any of the people the principal
claims were on the playground and, if they were on the playground, that
they were adequately supervising the children. In light of these facts, we
understand the trial court’s conclusion to be that, even if the facts were as
favorable to the defendants as the defendants allege, the court’s conclusion,
based on all of the evidence, was that the supervision was still inadequate.
