Estimating Fixed Effects: Perfect Prediction and Bias in Binary Response Panel Models, with an Application to the Hospital Readmissions Reduction Program

The maximum likelihood estimator for the regression coefficients, β, in a panel binary response model with fixed effects can be severely biased if N is large and T is small, a consequence of the incidental parameters problem. This has led to the development of conditional maximum likelihood estimators and, more recently, to estimators that remove the O(T–1) bias in β^. We add to this literature in two important ways. First, we focus on estimation of the fixed effects proper, as these have become increasingly important in applied work. Second, we build on a bias-reduction approach originally developed by Kosmidis and Firth (2009) for cross-section data, and show that in contrast to other proposals, the new estimator ensures finiteness of the fixed effects even in the absence of within-unit variation in the outcome. Results from a simulation study document favourable small sample properties. In an application to hospital data on patient readmission rates under the 2010 Affo

Assessing people with dementia participating in cognitive stimulation activities – A qualitative pilot video analysis exploring the importance of facilitating the participation

BACKGROUND: This pilot video analysis was part of a feasibility control study, which aimed to gain information about the size and variability of the changes in outcome measures to plan a substantive effect study. It compared a cognitive stimulation programme named Lifelong Learning with other existing dementia services. OBJECTIVE: The pilot video analysis explored how facilitation is performed, when assessing people with dementia with standardized measures, to ensure their participation in research. DESIGN: A test battery of five measures (Mini-Mental State Examination (MMSE), Quality of Life in Alzheimer's Disease Scale (QoL-AD), General Self-Efficacy Scale, Rosenberg Self-Esteem Scale and Hawthorn Friendship Scale) was used. Each assessment was video-recorded. The findings from a microanalysis of 10 videos are presented in this article. SETTING: The study involved 55 active participants with mild-to-moderate dementia in six municipalities in Northern Denmark. RESULTS: The identified themes related to supportive facilitation: Positive facilitator strategies; Creating a safe and comfortable environment; and to dilemmas in facilitation: Balancing multiple dilemmas and Balancing the MMSE test. DISCUSSION: Results are discussed in relation to using standardized measures. CONCLUSION: The quality of facilitation when using standardized measures is of great importance as it may influence the participant, the assessment and the answers given. The facilitation role needs to be thoroughly planned and executed with ethical consideration to improve the participation of vulnerable groups in research and ensure a person-centred approach. PATIENT OR PUBLIC CONTRIBUTION: The identified measures were chosen based upon previous qualitative results and user-involvement workshops with people with dementia