This document aims primarily to provide measure-validation details supplementary to the following
P. Whelehan, M. Pampaka, J. Boyd, S. Armstrong, A. Evans, G. Ozakinci, Development and validation of a novel measure of adverse patient positioning in mammography, Eur. J. Radiol. (2021) 109747. https://doi.org/10.1016/j.ejrad.2021.109747.
This supplement serves as an educational worked example of the Rasch measurement framework. Rasch measurement is a form of modern psychometric technique and our work provides the first known example of its use in the evaluation of clinical radiological image quality. Associated primary data are available upon request via the corresponding author named above.
An expert observer generated the primary data by reviewing mammographic images to judge the presence or absence of a set of features developed through theory and consultation with other experts. The items were designed to capture only and specifically those features hypothesised to have potential associations with pain or physical discomfort during mammography. For a full, general measure of mammography clinical image quality, additional items would be needed.
The validation data were generated through Rasch analysis, performed using Winsteps® software, which mathematically models the probability of having a correct response (or a present feature in this dataset) to an item in a given measurement instrument (e.g. questionnaire), as a function of the participant’s ability/position on the underlying construct under study.
|Number of pages||12|
|Publication status||Published - 12 May 2021|
- breast imaging
- mamography image quality
- Rasch model
- measurement theory