In this Section, we offer our thoughts on some of the frequently asked questions about pilot studies. These could be helpful to not only clinicians and trainees, but to anyone who is interested in health research.
• Can I publish the results of a pilot study?
- Yes, every attempt should be made to publish.
• Why is it important to publish the results of pilot studies?
- To provide information about feasibility to the research community to save resources being unnecessarily spent on studies that may not be feasible. Further, having such information can help researchers to avoid duplication of efforts in assessing feasibility.
- Finally, researchers have an ethical and scientific obligation to attempt publishing the results of every research endeavor. However, our focus should be on feasibility goals. Emphasis should not be placed on statistical significance when pilot studies are not powered to detect minimal clinically important differences. Such studies typically do not show statistically significant results - remember that underpowered studies (with no statistically significant results) are inconclusive, not negative since "no evidence of effect" is not "evidence of no effect" [27
• Can I combine data from a pilot with data from the main study?
- Yes, provided the sampling frame and methodologies are the same. This can increase the efficiency of the main study - see Section 5.
• Can I combine the results of a pilot with the results of another study or in a meta-analysis?
- Yes, provided the sampling frame and methodologies are the same.
- No, if the main study is reported and it includes the pilot study.
• Can the results of the pilot study be valid on their own, without existence of the main study
- Yes, if the results show that it is not feasible to proceed to the main study or there is insufficient funding.
• Can I apply for funding for a pilot study?
- Yes. Like any grant, it is important to justify the need for piloting.
- The pilot has to be placed in the context of the main study.
• Can I randomize patients in a pilot study?
- Yes. For a phase III pilot study, one of the goals could be to assess how a randomization procedure might work in the main study or whether the idea of randomization might be acceptable to patients [10
]. In general, it is always best for a pilot to maintain the same design as the main study.
• How can I use the information from a pilot to estimate the sample size?
- Use with caution, as results from pilot studies can potentially mislead sample size calculations.
- Consider supplementing the information with qualitative discussions with clinicians - see section 5; and
- Create a sample size table to acknowledge the uncertainty of the pilot information - see section 5.
• Can I use the results of a pilot study to treat my patients?
- Not a good idea!
- Pilot studies are primarily for assessing feasibility.
• What can I do with a failed or bad pilot study?
- No study is a complete failure; it can always be used as bad example! However, it is worth making clear that a pilot study that shows the main study is not likely to be feasible is not a failed (pilot) study. In fact, it is a success - because you avoided wasting scarce resources on a study destined for failure!