From store to screen: A first step in validating the Dutch Oxford Multiple Errands Test (OxMET-NL) for measuring...

Naturalistic assessment of executive functions (EF) remains a key challenge in clinical neuropsychology. Balancing reliability and ecological validity is essential, particularly in rehabilitation settings where every-day functioning is central to recovery. This study was aimed at providing a first step in assessing the psychometric properties of the Dutch Oxford Multiple Errands Test (OxMET-NL), a digital tablet-based adaptation of the shopping center Multiple Errands Test (MET), and directly compared performance with the in-person MET as an indicator of ecological validity. Participants included 51 individuals with acquired brain injury (ABI; 34 outpatients, 17 inpatients) and 70 cognitively healthy comparisons. We evaluated internal consistency, test-retest reliability, convergent and divergent validity with the MET and standard neuropsychological measures, and discriminability between the samples. Results indicated good internal consistency, whereas test-retest reliability was moderate, with large individual variability and faster retest performance. Convergent and divergent validity with the MET and neuropsychological tests was adequate. The task elicited strategy use that corresponded with the MET and daily life strategies. It also showed good discriminability between inpatients and comparisons, and between patients with and without EF difficulties, though less so between outpatients and comparisons. Although this study must be regarded in the light of the modest sample size, the OxMET-NL appears promising for assessing naturalistic, ecologically valid EF in ABI, but less appropriate for monitoring individual change over time.