Aberdeen University Research Archive >
6 - All research >
All research >
Please use this identifier to cite or link to this item:
|Title: ||Single imputation methods were inadequate for missing not at random (MNAR) quality of life data|
|Authors: ||Fielding, Shona|
McDonald, Alison Mary
McPherson, Gladys Campbell
Campbell, Marion Kay
RECORD Study Group
University of Aberdeen, School of Medicine & Dentistry, Division of Applied Health Sciences
|Keywords: ||Data Interpretation, Statistical|
Quality of Life
|Issue Date: ||4-Aug-2008|
|Citation: ||Fielding, S., Fayers, P.M., McDonald, A., McPherson, G., and Campbell, M.K. (2008). Single imputation methods were inadequate for missing not at random (MNAR) quality of life data. Health and Quality of Life Outcomes, 6(57).|
|Abstract: ||Objective: QoL data were routinely collected in a randomised controlled trial (RCT), which
employed a reminder system, retrieving about 50% of data originally missing. The objective was to
use this unique feature to evaluate possible missingness mechanisms and to assess the accuracy of simple imputation methods.
Methods: Those patients responding after reminder were regarded as providing missing
responses. A hypothesis test and a logistic regression approach were used to evaluate the
missingness mechanism. Simple imputation procedures were carried out on these missing scores
and the results compared to the actual observed scores.
Results: The hypothesis test and logistic regression approaches suggested the reminder data were missing not at random (MNAR). Reminder-response data showed that simple imputation
procedures utilising information collected close to the point of imputation (last value carried
forward, next value carried backward and last-and-next), were the best methods in this setting.
However, although these methods were the best of the simple imputation procedures considered,
they were not sufficiently accurate to be confident of obtaining unbiased results under imputation.
Conclusion: The use of the reminder data enabled the conclusion of possible MNAR data.
Evaluating this mechanism was important in determining if imputation was useful. Simple imputation was shown to be inadequate if MNAR are likely and alternative strategies should be considered.|
|Appears in Collections:||Applied Health Sciences research|
Items in AURA are protected by copyright, with all rights reserved, unless otherwise indicated.