Initial validation of the dimensions of home measure

Tammy Aplin, Chi-Wen Chien, Louise Gustafsson

Research has established a need to consider further aspects of the home environment in home modification provision and evaluation. The Dimensions of Home Measure (DOHM) was developed as a self-report outcome measurement tool for home modification practice to meet this need. Its development was informed by a literature review and qualitative exploration which identified six dimensions of the home environment: the physical, social, personal, temporal, occupational and societal dimensions which contribute to one's experience of home. This paper reports the initial evaluation of the validity of the DOHM. The DOHM was completed by 163 community dwelling older adults and people with disabilities. The Rasch measurement model was used to evaluate three aspects of construct validity: rating scale structure, unidimensionality and targeting. The five-point DOHM rating scale function was evaluated using Linacre's (2002) guidelines. The middle rating category did not function well, and this resulted in collapsing the rating scale from five to four points. The unidimensionality of the DOHM's subscales was supported by Rasch-based principal component analysis and item fit analysis. However, hierarchical results of item difficulties revealed significant gaps in each of the DOHM's subscales, indicating that more items will be needed to capture the full range of participant's experiences of home. The DOHM was developed to provide a relevant evaluation tool for home modification practice which comprehensively measures the home environment. This study identified preliminary validity of this tool, with revision and further psychometric validation required.