Article Text
Abstract
Background Factor analysis (FA) is a statistical technique that analyses underlying relationships in a data set. It is mainly used in the development and validation of questionnaires. Since valid outcome measures have become important in palliative care, criteria to judge the quality of FA are needed.
Aims To systematically review the current use and reporting of either exploratory or confirmatory FA and recommendations for FA, in order to design a checklist for reporting FA in the field of palliative care.
Methods In this systematic literature review, a hand search identified all studies using factor analytical techniques published in the four peer-reviewed journals Palliative Medicine, Journal of Pain & Symptom Management, Journal of Palliative Medicine, and the Journal of Palliative Care (inception – Mai 2010). Included were studies of any design, except reviews, reporting the results of one or several exploratory or confirmatory FA.
Results In 575 issues screened, 189 factor analytical studies were identified. Since the year 2000, FA has increasingly been applied in palliative care. It is mainly used in the development of new measures, to create subscales and to assess the multidimensionality of a measure, or in the evaluation (eg, translation) of an existing measure. The frequencies of different criteria (eg, ratio of sample size to number of items, factor extraction models, criteria for retaining factors, rotation techniques) will be analysed. On this basis, recommendations will be designed.
Conclusion The checklist developed provides guidance for journal editors, clinicians and researchers who need to judge or report a FA in palliative care.