This thesis examines the impact of using different researchers to capture quality of life outcome measures in Dementia randomised controlled trials. Chapter One starts with an introduction to Randomised Controlled Trials (RCT) and their role in evidence-based medicine and where they sit in the evidence hierarchy, before exploring the different types of biases that can arise in RCTs, which can impact upon research quality. The focus then turns to the importance of outcome measurement in RCTs and explores the issues of measurement error and the specific sources of instrument bias, particularly the impact of researcher bias on outcome measurement.
Chapter Two provides a brief introduction to Dementia and the impact Dementia can have on the quality of life of patients and their carers. The focus then turns to measuring quality of life in Dementia RCTs and the specific issues associated with this. Chapter Two concludes by focusing on the issues of instrument bias in Dementia RCTs and the influence of using multiple researchers to gather outcome data, before outlining the research questions to be addressed in this thesis.
Chapters Three describes the data used for the statistical analysis and includes a brief introduction to the RCT from which the data was derived and extracted. Chapters Four and Five detail the results of the statistical analysis conducted in order to assess the two different research questions proposed.
The thesis concludes in Chapter Six with a discussion of the results, a comparison of these results to other literature and the detail of the statistical methods adopted in comparison to other approaches used. It also describes the main limitations of the thesis and includes recommendations for future research and implications for current practice. The chapter ends with the final conclusions from the thesis, based on the analysis undertaken and its interpretation.