Is the Oral Health Impact Profile measuring up?

Objectives:

The aim of the study was to provide an empirical test of the construct validity of the Oral Health Impact Profile (Slade and Spencer, 1994) as a measure of Locker's (1988) conceptual model of oral health.

Methods:

A secondary analysis of data from the Ontario Study of Older Adults (Locker, 1993) was carried out using structural equation modelling to assess the degree to which scale items measure the construct they are supposed to measure (within-construct validity) and whether relations between constructs are as hypothesised by Locker's model (between-construct validity).

Results:

The findings indicated that the OHIP as currently conceived does not have adequate within construct validity. Scale items did not always measure the construct they were supposed to measure, some items within a construct were redundant, many measured more than one construct, and the scale did not represent seven separate constructs of oral health as originally devised. Following reconceptualisation of the scale, the revised four-factor 23 item version was a better fit to the data, and had adequate between-construct validity. That is, the relationships between constructs as hypothesised within Locker's model were significant.

Conclusion:

These findings do not provide support for the conceptual basis of the OHIP as a measure of Locker's model of oral health. The need for a revised measure of oral health quality of life is discussed, and further conceptual development of Locker's model is highlighted.