Numerous studies have examined the association between safety and primary school-aged children\'s forms of active mobility. However, variations in studies\' measurement methods and the elements addressed have contributed to inconsistencies in research outcomes, which may be forming a barrier to advancing researchers\' knowledge about this field. To assess where current research stands, we have synthesised the methodological measures in studies that examined the effects of neighbourhood safety exposure (perceived and measured) on children\'s outdoor active mobility behaviour and used this analysis to propose future research directions.
A systematic search of the literature in six electronic databases was conducted using pre-defined eligibility criteria and was concluded in July 2020. Two reviewers screened the literature abstracts to determine the studies\' inclusion, and two reviewers independently conducted a methodological quality assessment to rate the included studies.
Twenty-five peer-reviewed studies met the inclusion criteria. Active mobility behaviour and health characteristics were measured objectively in 12 out of the 25 studies and were reported in another 13 studies. Twenty-one studies overlooked spatiotemporal dimensions in their analyses and outputs. Delineations of children\'s neighbourhoods varied within 10 studies\' objective measures, and the 15 studies that opted for subjective measures. Safety perceptions obtained in 22 studies were mostly static and primarily collected via parents, and dissimilarities in actual safety measurement methods were present in 6 studies. The identified schematic constraints in studies\' measurement methods assisted in outlining a three-dimensional relationship between \'what\' (determinants), \'where\' (spatial) and \'when\' (time) within a methodological conceptual framework.
The absence of standardised measurement methods among relevant studies may have led to the current diversity in findings regarding active mobility, spatial (locality) and temporal (time) characteristics, the neighbourhood, and the representation of safety. Ignorance of the existing gaps and heterogeneity in measures may impact the reliability of evidence and poses a limitation when synthesising findings, which could result in serious biases for policymakers. Given the increasing interest in children\'s health studies, we suggested alternatives in the design and method of measures that may guide future evidence-based research for policymakers who aim to improve children\'s active mobility and safety.