Objectives: To compare parent/carer proxy-reported dental caries experience of their 5-year-old child with epidemiological survey clinician examination of caries experience in the same children. To determine any differences in the accuracy by area-based socioeconomic group. Methods: A cross-sectional data linkage study linked data from the Growing Up in Scotland (GUS) study and the National Dental Inspection Programme (NDIP) school epidemiology survey. Parent/carer proxy-reported caries experience was compared with clinicianmeasured caries experience on n=3008 children, and data were stratified by home-residential area-based socioeconomic deprivation levels (Scottish Index of Multiple Deprivation (SIMD)). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated overall and stratified by SIMD. Results: Overall, parent/carer proxy-reporting had low sensitivity (42.3% 95%CI: 39.0, 45.7) that decreased with decreasing deprivation (SIMD-1(most deprived): 49.4% to SIMD-5 (least deprived): 37.2%). Specificity remained consistently high overall and across area-based socioeconomic deprivation levels (overall=96.2%, 95%CI: 95.3, 97.0; SIMD-1: 94.4% SIMD-5: 97.8%). In children whose parents/carers reported them to have caries experience (GUS) a high percentage were found to have caries experience (NDIP) (PPV=81.8%, 95%CI: 78.2, 84.9). Conclusion: Parent/carer proxy-reporting of caries experience in 5-year-old children had very low sensitivity and was lowest in children from the least deprived areas. In contrast, parents/carers who reported their child had caries experience did so reasonably accurately. This study concludes that proxy reporting caries experience is not sufficiently sensitive to replace clinician examination in assessing dental caries experience in surveys of child populations and highlights the importance of data linkage to routine datasets. Keywords: epidemiology, socioeconomic factors, dental caries, self-report, child health, medical record linkage