CASP Randomised Controlled Trial Standard Checklist:
11 questions to help you make sense of a randomised controlled trial (RCT)
Main issues for consideration: Several aspects need to be considered when appraising a
randomised controlled trial:
Is the basic study design valid for a randomised
controlled trial? (Section A)
Was the study methodologically sound? (Section B)
What are the results? (Section C)
Will the results help locally? (Section D)
The 11 questions in the checklist are designed to help you think about these aspects
systematically.
How to use this appraisal tool: The first three questions (Section A) are screening questions
about the validity of the basic study design and can be answered quickly. If, in light of your
responses to Section A, you think the study design is valid, continue to Section B to assess
whether the study was methodologically sound and if it is worth continuing with the appraisal by
answering the remaining questions in Sections C and D.
Record ‘Yes’, ‘No’ or ‘Can’t tell’ in response to the questions. Prompts below all but one of the
questions highlight the issues it is important to consider. Record the reasons for your answers
in the space provided. As CASP checklists were designed to be used as educational/teaching
tools in a workshop setting, we do not recommend using a scoring system.
About CASP Checklists: The CASP RCT checklist was originally based on JAMA Users’ guides to the
medical literature 1994 (adapted from Guyatt GH, Sackett DL and Cook DJ), and piloted with
healthcare practitioners. This version has been updated taking into account the CONSORT 2010
guideline ( accessed 16 September 2020).
Citation: CASP recommends using the Harvard style, i.e. Critical Appraisal Skills Programme
(2020). CASP (insert name of checklist i.e. Randomised Controlled Trial) Checklist. [online]
Available at: insert URL. Accessed: insert date accessed.
©CASP this work is licensed under the Creative Commons Attribution – Non-Commercial- Share
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Study and citation: …………………………………………………………………………………………………………
Section A: Is the basic study design valid for a randomised controlled trial?
1. Did the study address a clearly focused
research question?
CONSIDER:
Was the study designed to assess the outcomes
of an intervention?
Is the research question ‘focused’ in terms of:
• Population studied
• Intervention given
• Comparator chosen
• Outcomes measured?
Yes No Can’t tell
o o
2. Was the assignment of participants to
interventions randomised?
CONSIDER:
• How was randomisation carried out? Was
the method appropriate?
• Was randomisation sufficient to eliminate
systematic bias?
• Was the allocation sequence concealed
from investigators and participants?
Yes No Can’t tell
o o o
3. Were all participants who entered the study
accounted for at its conclusion?
CONSIDER:
• Were losses to follow-up and exclusions
after randomisation accounted for?
• Were participants analysed in the study
groups to which they were randomised
(intention-to-treat analysis)?
• Was the study stopped early? If so, what
was the reason?
Yes No Can’t tell
o o o
Section B: Was the study methodologically sound?
4.
• Were the participants ‘blind’ to
intervention they were given?
• Were the investigators ‘blind’ to the
intervention they were giving to
participants?
• Were the people assessing/analysing
outcome/s ‘blinded’?
Yes No Can’t tell
o o o
o o
o o o
5. Were the study groups similar at the start of
the randomised controlled trial?
CONSIDER:
• Were the baseline characteristics of each
study group (e.g. age, sex, socio-economic
group) clearly set out?
• Were there any differences between the
study groups that could affect the
outcome/s?
Yes No Can’t tell
o o o
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6. Apart from the experimental intervention, did
each study group receive the same level of
care (that is, were they treated equally)?
CONSIDER:
• Was there a clearly defined study protocol?
• If any additional interventions were given
(e.g. tests or treatments), were they similar
between the study groups?
• Were the follow-up intervals the same for
each study group?
Yes No Can’t tell
o o o
Section C: What are the results?
7. Were the effects of intervention reported
comprehensively?
CONSIDER:
•
• What outcomes were measured, and were
they clearly specified?
• How were the results expressed? For
binary outcomes, were relative and
absolute effects reported?
• Were the results reported for each
outcome in each study group at each
follow-up interval?
• Was there any missing or incomplete data?
• Was there differential drop-out between the
study groups that could affect the results?
• Were potential sources of bias identified?
• Which statistical tests were used?
• Were p values reported?
Yes No Can’t tell
o o o
8. Was the precision of the estimate of the
intervention or treatment effect reported?
CONSIDER:
• Were confidence intervals (CIs) reported?
Yes No Can’t tell
o o o
9. Do the benefits of the experimental
intervention outweigh the harms and costs?
CONSIDER:
• What was the size of the intervention or
treatment effect?
• Were harms or unintended effects
reported for each study group?
• Was a cost-effectiveness analysis
undertaken? (Cost-effectiveness analysis
allows a comparison to be made between
different interventions used in the care of
the same condition or problem.)
Yes No Can’t tell
o o o
Was a power calculation underta en?
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Section D: Will the results help locally?
10. Can the results be applied to your local
population/in your context?
CONSIDER:
• Are the study participants similar to the
people in your care?
• Would any differences between your
population and the study participants alter
the outcomes reported in the study?
• Are the outcomes important to your
population?
• Are there any outcomes you would have
wanted information on that have not been
studied or reported?
• Are there any limitations of the study that
would affect your decision?
Yes No Can’t tell
o o o
11. Would the experimental intervention provide
greater value to the people in your care than
any of the existing interventions?
CONSIDER:
• What resources are needed to introduce
this intervention taking into account time,
finances, and skills development or training
needs?
• Are you able to disinvest resources in one
or more existing interventions in order to
be able to re-invest in the new
intervention?
Yes No Can’t tell
o o o
APPRAISAL SUMMARY: Record key points from your critical appraisal in this box. What is your
conclusion about the paper? Would you use it to change your practice or to recommend changes to
care/interventions used by your organisation? Could you judiciously implement this intervention
without delay?
