OBJECTIVES: Development and validation of a simple stool diary for caretakers collecting data on stool frequency and consistency among young children in a low-income country.

METHODS: Focus group studies evaluated how diarrhea was understood by caregivers (content validity). The sensitivity, reliability, and correlations between dehydration and diary scores (construct validity) were tested in a clinical trial.

RESULTS: Caregivers recognized and understood the concept and severity of diarrhea. Stool frequency and liquid consistency decreased in children admitted with diarrhea (p < 0.0001 for both), confirming good sensitivity of the diary. High reliability was obtained after a few days of training. The caregiver intra-correlation coefficients were 0.66 (0.55-0.77) and 0.75 (0.66-0.84) after two and seven days of training, respectively, and subjective staff evaluation of caregiver scores showed that ≤6% of caregivers had low scoring abilities after three days. The degree of dehydration (4-point score) was correlated with both increasing stool frequency and liquid stool consistency (+0.2 points (0.07-0.3), p = 0.0018 for six or more diarrheal stools, compared to three or more diarrheal stools per day, and +0.5 points (0.3-0.6), p < 0.0001 for diarrheal episodes with three or more watery stools/day compared to episodes with three or more "watery + abnormally loose + loose" stools per day).

CONCLUSIONS: The diary showed high validity, good reliability, and high sensitivity. After three days of training, caregivers with mainly no or limited education could report stool consistency with good reliability. Stool consistency, which correlated strongly with dehydration, may be considered an important marker of diarrhea severity in future research.