Objective: To determine the reliability and acceptability of the Uniscale.
Methods: Two studies were conducted from December 2000 to February 2001 in Iran. In the first study, weights of subjects were obtained using the Uniscale and compared with weights obtained from the currently used scale. The sample comprised pregnant women and children under 5 years old. The main measure was reliability, which was assessed by two indicators: intra-instrument error for each of the two scales, and inter-instrument error. The second study was a descriptive study designed to test providers' perceptions of acceptability of Uniscale measurements.
Results: In the first study, a total of 458 subjects participated in the study. Overall, mean values of repeated measurements using each of the scales (intra-instrument error) were not significantly different. There was no significant difference between the weight measurements of the two scales (inter-instrument error) when weighing children, but a significant difference was detected when weighing pregnant women (p < 0.001). In the second study, 54 providers were included. The proportions of providers who recommended use of the Uniscale for children under 2 years, children 2-5 years and pregnant women were 57%, 75% and 80%, respectively.
Conclusions: The Uniscale had the same accuracy as the current scale when weighing children. However, for use with adults, we suggest additional studies be conducted with increased training of providers because we found that measurements were influenced by individual variation in use. It is recommended that new versions of mother-child scales be developed that are more user friendly.