Duff, Mengoni, Bailey and Snowling ("Journal of Research in Reading," 38: 109-123; 2015) evaluated the sensitivity and specificity of the phonics screening check against two reference standards. This report aims to correct a minor data error in the original article and to present further analysis of the data. The methods used are calculation of predictive values of the phonics screening check in addition to sensitivity and specificity, and evaluation of agreement between the reference tests. Predictive values are important indicators of screening test quality. The positive predictive value of the phonics check is low (0.31) when compared with a standardised reading test but high (0.84) when compared with teachers' phonic phases judgements, reflecting poor agreement (kappa = 0.27) between reference tests. Results have implications for practice in terms of choice of reference standard and choice of threshold criterion for children to pass the screening check. Longitudinal data are needed to assess the predictive validity and utility of the check.