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Effect of a 1‐month vs. a 12‐month reference period on responses to the 14‐item Oral Health Impact Profile
Author(s) -
Sutinen Saila,
Lahti Satu,
Nuttall Nigel M.,
Sanders Anne E.,
Steele Jimmy G.,
Allen P. Finbarr,
Slade Gary D.
Publication year - 2007
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2007.00442.x
Subject(s) - medicine , oral health , confidence interval , reference values , dentistry
The length of the reference period used in surveys of subjective oral health may have a marked influence on the responses obtained. We aimed to evaluate the effect of a 1‐month (RP‐1) vs. a 12‐month (RP‐12) reference period in the Oral Health Impact Profile (OHIP‐14) questionnaire. Using a randomized cross‐over design, RP‐1 and RP‐12 OHIP‐14 questionnaires were administered, 1 month apart, to two samples of Finnish adults, namely people awaiting orthognathic surgery ( n = 104) and non‐patient workers ( n = 111). The effect of the reference period was computed by subtracting RP‐1 OHIP‐14 severity scores from RP‐12 OHIP‐14 severity scores ( Δ RP). Potential order effects were assessed by comparing Δ RP between groups completing the RP‐1 vs. the RP‐12 questionnaire first. Mean OHIP‐14 severity scores were slightly higher when the RP‐12 questionnaire was administered first, but mean Δ RP values were below the value of 2.5 considered clinically meaningful, and all 95% confidence intervals for Δ RP included zero. No order effects in the OHIP‐14 severity scores were observed. Therefore, although a standardized reference period of 12 months is recommended, in population surveys the use of a shorter reference period does not appear to influence responses.