Book contents
- Rethinking Clinical Research
- Rethinking Clinical Research
- Copyright page
- Contents
- Acknowledgments
- Introduction
- Part I Fundamentals
- Part II Rethinking Research
- 4 Asking the Right Questions
- 5 Bias in Randomized Controlled Trials
- 6 Is Bigger Always Better?
- 7 Achieving Transparency
- 8 Understanding and Restraining Study Costs
- 9 Implementation
- 10 Health Outcomes
- 11 Confronting the Crises in Peer Review and Academic Publishing
- 12 Ontologies
- Part III Case Studies
- Index
- References
5 - Bias in Randomized Controlled Trials
from Part II - Rethinking Research
Published online by Cambridge University Press: 13 March 2025
Book contents
- Rethinking Clinical Research
- Rethinking Clinical Research
- Copyright page
- Contents
- Acknowledgments
- Introduction
- Part I Fundamentals
- Part II Rethinking Research
- 4 Asking the Right Questions
- 5 Bias in Randomized Controlled Trials
- 6 Is Bigger Always Better?
- 7 Achieving Transparency
- 8 Understanding and Restraining Study Costs
- 9 Implementation
- 10 Health Outcomes
- 11 Confronting the Crises in Peer Review and Academic Publishing
- 12 Ontologies
- Part III Case Studies
- Index
- References
Summary
In hierarchies of research evidence, the randomized controlled trial (RCT) usually appears near the top of the pyramid. RCTs are usually considered to be free of bias; systematic reviews of the literature may exclude studies that are not RCTs. Although controlled trials are excellent methods for establishing causation, they do not assure freedom from systematic bias. This chapter explores biases that are common among RCTs. In particular, we report on the practice of systematically excluding study participants who do not meet specific criteria. It is not uncommon for 90 percent of potential volunteers to be turned away. Common grounds for exclusion include comorbidities, even though living with multiple chronic conditions is almost universal among older adults. The selection of the control group can also increase bias. Control groups might be selected specifically because they increase the likely difference between treated and control conditions. The implications of biases in our RCTs are discussed.
Keywords
- Type
- Chapter
- Information
- Rethinking Clinical ResearchMethodology and Ethics, pp. 97 - 116Publisher: Cambridge University PressPrint publication year: 2025
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