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Are treatment effect assumptions in orthodontic studies overoptimistic?
Jadbinder Seehra1, Daniel Stonehouse-Smith1, Martyn T Cobourne1
1Department of Orthodontics, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, Floor 25, Guy's Hospital, Guy's and St Thomas NHS Foundation Trust, London, UK.
European Journal of Orthodontics
|May 15, 2021
Summary
Clinical trial sample size assumptions are often overoptimistic. This study found assumed treatment effects were significantly larger than observed effects, highlighting a need for careful design considerations in orthodontic research to reduce waste.
Area of Science:
- Clinical research methodology
- Biostatistics
- Orthodontic study design
Background:
- Clinical trial design requires appropriate assumptions for accurate sample size calculation.
- Evidence suggests sample size assumptions in medical literature may be overly optimistic.
- Overly optimistic assumptions can lead to unreliable study results and research waste.
Purpose of the Study:
- To compare assumed treatment effects with observed effects in orthodontic studies.
- To identify and quantify overoptimistic treatment effect assumptions at the study design stage.
- To provide recommendations for improving the reliability of clinical study designs.
Main Methods:
- Systematic reviews (SRs) with meta-analyses on continuous outcomes published between 2010-2019 were identified.
- Data on sample size calculation, assumed treatment effects, and observed effects were extracted from SRs and primary trials.
- Assumed treatment effects were compared to observed effects using statistical tests.
Main Results:
- Eighty-five SRs comprising 347 primary trials were analyzed.
- Sample size details were reported in only 31.7% of studies, with assumed treatment effects reported in just 37 of those.
- A significant difference was found between assumed and observed treatment effects (P < 0.001), with assumed effects being larger.
Conclusions:
- Overoptimistic treatment effect assumptions are prevalent in orthodontic study designs.
- Careful consideration of assumptions during the design phase is crucial.
- Improving design assumptions can enhance the reliability of orthodontic research and minimize wasted resources.
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