dc.contributor.author | Fielding, Shona | en |
dc.contributor.author | Fayers, Peter | en |
dc.contributor.author | McDonald, Alison Mary | en |
dc.contributor.author | McPherson, Gladys Campbell | en |
dc.contributor.author | Campbell, Marion Kay | en |
dc.contributor.author | RECORD Study Group | en |
dc.date.accessioned | 2009-03-16T11:29:03Z | |
dc.date.available | 2009-03-16T11:29:03Z | |
dc.date.issued | 2008-08-04 | |
dc.identifier.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). | en |
dc.identifier.issn | 1477-7525 | |
dc.identifier.uri | http://hdl.handle.net/2164/268 | |
dc.description.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. | en |
dc.description.sponsorship | The MRC funded the central organisation of RECORD, and Shire Pharmaceuticals Group plc funded the drugs, which were manufactured by Nycomed Ltd. The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health Directorate. Shona Fielding is also currently funded by the Chief Scientist Office on a Research Training Fellowship (CZF/1/31) | en |
dc.format.extent | 291329 bytes | |
dc.format.mimetype | application/pdf | |
dc.language.iso | en | en |
dc.publisher | BMC | en |
dc.subject | Data Interpretation, Statistical | en |
dc.subject | Quality of Life | en |
dc.subject | Questionnaires | en |
dc.subject.lcc | RA Public aspects of medicine | en |
dc.title | Single imputation methods were inadequate for missing not at random (MNAR) quality of life data | en |
dc.type | Journal Article | en |
dc.type | Text | en |
dc.contributor.institution | University of Aberdeen, School of Medicine & Dentistry, Division of Applied Health Sciences | en |
dc.description.status | Peer reviewed | en |
dc.description.version | Publisher PDF | en |
dc.identifier.doi | http://dx.doi.org/10.1186/1477-7525-6-57 | |