Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes
Melanie L Bell,1 Amy L Whitehead,2 Steven A Julious2 1Department of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA; 2Medical Statistics Group, Design, Trials and Statistics, School of Health and Related Research (ScHARR), Unive...
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| Format: | Article |
| Language: | English |
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Dove Medical Press
2018-01-01
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| Series: | Clinical Epidemiology |
| Subjects: | |
| Online Access: | https://www.dovepress.com/guidance-for-using-pilot-studies-to-inform-the-design-of-intervention--peer-reviewed-article-CLEP |
| _version_ | 1818590417551097856 |
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| author | Bell ML Whitehead AL Julious SA |
| author_facet | Bell ML Whitehead AL Julious SA |
| author_sort | Bell ML |
| collection | DOAJ |
| description | Melanie L Bell,1 Amy L Whitehead,2 Steven A Julious2 1Department of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA; 2Medical Statistics Group, Design, Trials and Statistics, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK Background: A pilot study can be an important step in the assessment of an intervention by providing information to design the future definitive trial. Pilot studies can be used to estimate the recruitment and retention rates and population variance and to provide preliminary evidence of efficacy potential. However, estimation is poor because pilot studies are small, so sensitivity analyses for the main trial’s sample size calculations should be undertaken.Methods: We demonstrate how to carry out easy-to-perform sensitivity analysis for designing trials based on pilot data using an example. Furthermore, we introduce rules of thumb for the size of the pilot study so that the overall sample size, for both pilot and main trials, is minimized.Results: The example illustrates how sample size estimates for the main trial can alter dramatically by plausibly varying assumptions. Required sample size for 90% power varied from 392 to 692 depending on assumptions. Some scenarios were not feasible based on the pilot study recruitment and retention rates.Conclusion: Pilot studies can be used to help design the main trial, but caution should be exercised. We recommend the use of sensitivity analyses to assess the robustness of the design assumptions for a main trial. Keywords: pilot, feasibility, sample size, power, randomized controlled trial, sensitivity analysis |
| first_indexed | 2024-12-16T09:56:13Z |
| format | Article |
| id | doaj.art-9967dfb6073d40cc80169ac3860708fe |
| institution | Directory Open Access Journal |
| issn | 1179-1349 |
| language | English |
| last_indexed | 2024-12-16T09:56:13Z |
| publishDate | 2018-01-01 |
| publisher | Dove Medical Press |
| record_format | Article |
| series | Clinical Epidemiology |
| spelling | doaj.art-9967dfb6073d40cc80169ac3860708fe2022-12-21T22:35:54ZengDove Medical PressClinical Epidemiology1179-13492018-01-01Volume 1015315736428Guidance for using pilot studies to inform the design of intervention trials with continuous outcomesBell MLWhitehead ALJulious SAMelanie L Bell,1 Amy L Whitehead,2 Steven A Julious2 1Department of Epidemiology and Biostatistics, Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA; 2Medical Statistics Group, Design, Trials and Statistics, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK Background: A pilot study can be an important step in the assessment of an intervention by providing information to design the future definitive trial. Pilot studies can be used to estimate the recruitment and retention rates and population variance and to provide preliminary evidence of efficacy potential. However, estimation is poor because pilot studies are small, so sensitivity analyses for the main trial’s sample size calculations should be undertaken.Methods: We demonstrate how to carry out easy-to-perform sensitivity analysis for designing trials based on pilot data using an example. Furthermore, we introduce rules of thumb for the size of the pilot study so that the overall sample size, for both pilot and main trials, is minimized.Results: The example illustrates how sample size estimates for the main trial can alter dramatically by plausibly varying assumptions. Required sample size for 90% power varied from 392 to 692 depending on assumptions. Some scenarios were not feasible based on the pilot study recruitment and retention rates.Conclusion: Pilot studies can be used to help design the main trial, but caution should be exercised. We recommend the use of sensitivity analyses to assess the robustness of the design assumptions for a main trial. Keywords: pilot, feasibility, sample size, power, randomized controlled trial, sensitivity analysishttps://www.dovepress.com/guidance-for-using-pilot-studies-to-inform-the-design-of-intervention--peer-reviewed-article-CLEPpilotfeasibilitysample sizepowerrandomized controlled trialsensitivity analysis Running head: Using pilots to design main trials |
| spellingShingle | Bell ML Whitehead AL Julious SA Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes Clinical Epidemiology pilot feasibility sample size power randomized controlled trial sensitivity analysis Running head: Using pilots to design main trials |
| title | Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes |
| title_full | Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes |
| title_fullStr | Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes |
| title_full_unstemmed | Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes |
| title_short | Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes |
| title_sort | guidance for using pilot studies to inform the design of intervention trials with continuous outcomes |
| topic | pilot feasibility sample size power randomized controlled trial sensitivity analysis Running head: Using pilots to design main trials |
| url | https://www.dovepress.com/guidance-for-using-pilot-studies-to-inform-the-design-of-intervention--peer-reviewed-article-CLEP |
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