Reliability of a stool consistency classification system.
OBJECTIVE
Reliability and validity are important measures of the quality of a research or clinical instrument. This research determined the inter-rater and test-retest reliability of a stool consistency classification system and the agreement between the subjects' and expert investigators' classifications.


METHODS
Two studies were conducted with adult volunteers. Stool consistency was described by words only and words + diagrams. To determine inter-rater reliability, subjects in each of 3 groups (20 nurses, 20 nursing students, and 20 lay persons) classified the consistency of 12 stool specimens. To determine test-retest reliability, 43 additional subjects classified the consistency of 9 stool specimens in 2 sessions.


METHODS
Outcome measures were reported per individual stool specimen and for all stool specimens. The outcome measures were the consistency classifications by the 3 groups of raters when the 2 types of descriptors (word only and word + diagram) were used. Other outcomes were the consistency classifications of the subjects on the 2 days of stool evaluation and the classifications of the subjects compared with those of the investigators.


RESULTS
No significant difference was found among the stool consistency classifications among nurses, nursing students, or lay persons. Classifications were similar for 11 of 12 stool specimens when either word-only or word + diagram descriptions were used. No significant difference was found among the classifications between days 1 and 2. At least 75% of the subjects' classifications of stool consistency in both studies agreed highly with those of the investigators.


CONCLUSIONS
The reliability and validity of the stool consistency classification system are good. The word-only descriptions of the consistency classifications appeared to be equally as effective as the word + diagram descriptions.
Zimmaro Bliss
D
D
University of Minnesota School of Nursing, Minneapolis, USA. bliss@tc.umn.edu
Larson
S J
SJ
Burr
J K
JK
Savik
K
K
D000328:Adult; D000704:Analysis of Variance; D005242:Fecal Incontinence / Q000451:nursing*; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D009730:Nursing Assessment / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric