Explainer · Plain-language

Pilot Study: Definition, Meaning & Examples | CASRAI

A pilot study is a small-scale preliminary investigation conducted before a main study to test its feasibility, refine procedures, and identify problems while they are still cheap to fix. It is about rehearsal and improvement, not hypothesis testing.

CASRAI plain-language explainers — clear answers to recurring research-administration questions

The step most authors miss

Doing CRediT right? Don’t stop at the statement.

A CRediT statement credits you inside one paper. The recognition CRediT was built for happens when those roles are tied to you, persistently. Sign in with your ORCID — free — and claim your CRediT contributions on casrai.org, the home of the standard. They become a verified, portable part of your identity, not a line that disappears into one PDF.

Free: claim your contributions, then export a journal-ready CRediT statement, schema.org structured data, JATS XML, CSV or BibTeX — and preview your public profile. A membership publishes that profile publicly and verifies the journals you serve.

A rehearsal for the main study

A pilot study trials the procedures of a planned project on a small scale to see whether they are practicable. Researchers use it to check that questionnaires are understood as intended, that equipment and software behave, that data-collection and recording workflows are sound, and that recruitment and consent processes function. Treating the main study’s design as something to be tested — rather than assumed — lets investigators catch and correct problems while changes are still inexpensive and low-risk.

What a pilot is for

The core aims of a pilot are feasibility and refinement. It can reveal whether enough eligible participants can be recruited and retained, how long procedures actually take, whether instructions are clear, and where measures or protocols need amending. Pilots also help train the research team and test analysis pipelines on realistic data. The deliverable is a better, more robust protocol for the definitive study, together with practical estimates of timing, cost, and likely attrition.

What a pilot is not for

A pilot study is not a miniature confirmatory study. Its sample is usually too small to test the research hypothesis with any power, and reporting its outcome results as if they were findings is a common error. Importantly, methodologists caution against using a pilot’s observed effect size to power the main trial, because small-sample estimates are unstable and can badly mislead a power calculation. A pilot answers "can we do this study, and how?", not "is the hypothesis true?".

Pilots, feasibility studies and reporting

In some fields, especially trials, a distinction is drawn between feasibility studies (which ask whether a future study can be done) and pilot studies (which test a scaled-down version of the actual design); the terms overlap in practice. Either way, good practice is to define clear progression criteria in advance and to report pilots transparently — there are reporting guidelines (such as the CONSORT extension for pilot and feasibility trials) that set out what such studies should disclose, so their lessons are usable and not over-interpreted.

Key facts

At a glance

Definition: A small preliminary study testing a main study’s feasibility
Purpose: Refine procedures, instruments, recruitment and logistics
Not for: Testing the main hypothesis or proving an effect
Caution: Do not use its effect size to power the main study
Related term: Feasibility study (overlapping but distinct emphasis)
Reporting: Guided by extensions such as CONSORT for pilot trials

Common misconceptions

What people often get wrong

Often heard: A pilot study tests whether the hypothesis is true.

Actually: No — its purpose is feasibility and refinement. Its sample is too small to test the hypothesis with adequate power.

Often heard: You should use the pilot’s effect size to power the main trial.

Actually: No — small-sample effect estimates are unstable and can seriously mislead a power calculation. Pilots are not designed for this.

Often heard: A pilot study and a feasibility study are exactly the same.

Actually: No — they overlap, but a feasibility study asks whether a study can be done, while a pilot tests a scaled-down version of the actual design.

Going deeper