Straight-Lining and Response Quality in the 2024 Indonesian Nutritional Status Survey: Respondent, Household, and Regional Correlates

Knowledge and attitude scales in national health surveys are used to describe how caregivers understand stunting, yet their validity depends on whether respondents consider each item. This study examined straight-lining, giving identical answers to every item of a scale, in the 2024 Indonesian Nutritional Status Survey. A cross-sectional secondary analysis included 273,959 caregivers who answered a 20-item stunting knowledge and attitude scale containing five negatively worded statements, using survey-weighted logistic regression and multilevel models. Straight-lining occurred in 4.6% of caregivers (95% confidence interval 4.4–4.7), ranged from 0.7% to 29.5% across provinces, and in 70.0% of cases consisted of answering “agree” to every statement. It was less common in the wealthiest households (adjusted odds ratio 0.54) and more common where the child had never had a maternal and child health handbook (1.49), where the respondent did not know the mother’s age at pregnancy (2.71), in rural areas (1.23) and in most regions outside Java and Bali. Straight-lining was strongly clustered: 5% of survey clusters contained 55.6% of all straight-liners. Excluding straight-liners barely changed reliability (0.723 versus 0.720). Straight-lining reflects respondent ability and engagement but is concentrated in particular clusters, pointing to fieldwork practice as a target for quality control.