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Arquivos Brasileiros de Oftalmologia

Print version ISSN 0004-2749On-line version ISSN 1678-2925

Arq. Bras. Oftalmol. vol.82 no.2 São Paulo Mar./Apr. 2019 


PICOT: Imprescriptible items in a clinical research question

PICOT: Itens imprescindíveis em uma pesquisa clínica

Rodrigo Pessoa Cavalcanti Lira1  2 

Eduardo Melani Rocha3 

1Departamento de Oftalmologia, Universidade Federal de Pernambuco, Recife, PE, Brazil.

2Departamento de Oftalmologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.

3Departamento de Oftalmologia, Otorinolaringologioa e Cirurgia de Cabeça e Pescoço, Faculdade de Medicina, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

Important ingredients in scientific research can be found in the acronym PICOT (Population, Intervention, Control, Outcome, and Time), which lists 5 fundamental topics, particularly in clinical trials.

In a clinical trial, a poorly devised research question can affect the choice of study design, potentially lead to futility, and thus impede the chance of determining anything of clinical significance, which affects the potential for publication and possibly raise criticism regarding the waste of time and investment as well as questions regarding ethical issues(1).

A checklist for a research question in a clinical trial must contain, at a minimum, the following: population (P) – to cite the eligibility criteria for participants and report the settings and locations in addition to where the data were collected; intervention (I) and control (C) – to explain the interventions for each group with sufficient details to allow for replication, including how and when the interventions were administered; and outcome (O) and time (T) – to completely define pre-specified primary and secondary outcome measures, including how and when they were assessed(2).

A hypothetical example of a research question would be: Does the addition of intravitreous steroids (I) reduce retinal thickness (O1) and/or improve visual acuity (O2) at 12 months (T) in eyes receiving continued intravitreous anti-vascular endothelial growth factor (VEGF) therapy (C) for diabetic macular edema (P)?

Likewise, the hypothetical findings would be: In this phase 3, randomized, clinical trial including 200 eyes with diabetic macular edema (P), the addition of intra­vitreous steroids to continued anti-VEGF therapy (I) reduces retinal thickness (O1) at 12 months (T), but does not improve visual acuity (O2) more than continued therapy alone (C).

Although PICOT resumes the key points of clinical trials (and most other research designs), other important items supporting a well-conducted study include sample size, randomization, blinding, statistical methods, limitations, harms, ethical issues, and funding.

A helpful tool for authors is the Enhancing the QUAlity and Transparency Of health Research website at From this site, a detailed checklist for different study designs may be downloaded, for example, CONSORT (clinical trials), STROBE (observational studies), PRISMA (systematic reviews), and ARRIVE (animal pre-clinical studies).

PICOT is a model that outlines clinical research ques­tions and acts as a framework to ask the researcher spe­cific questions about different aspects of the investigation. It is a relevant part of evidence-based research and a guide for high-quality clinical projects.

Funding: No specific financial support was available for this study.


Farrugia P, Petrisor BA, Farrokhyar F, Bhandari M. Practical tips for surgical research: Research questions, hypotheses and objectives. Can J Surg. 2010;53(4):278-81. [ Links ]

Moher D, Hopewell S, Schulz KF, Montori V, Gøtzsche PC, Devereaux PJ, Elbourne D, Egger M, Altman DG; CONSORT. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. Int J Surg. 2012;10(1):28-55. [ Links ]

Received: September 12, 2018; Accepted: September 27, 2018

Corresponding author: Rodrigo Pessoa Cavalcanti Lira. Rua Irma Maria David, 200/1302 - Recife, PE - 52061-070 - Brazil. E-mail:

Disclosure of potential conflicts of interest: None of the authors have any potential conflicts of interest to disclose.

Creative Commons License This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited