Background Many outcome measures for young people exist, but the choices for services are limited when seeking measures that (a) are free to use in both paper and electronic format, and (b) have evidence of good psychometric properties. Method Data on the Young Person's Clinical Outcomes in Routine Evaluation (YP‐CORE), completed by young people aged 11–16, are reported for a clinical sample (N = 1269) drawn from seven services and a nonclinical sample (N = 380). Analyses report item omission, reliability, referential distributions and sensitivity to change. Results The YP‐CORE had a very low rate of missing items, with 95.6% of forms at preintervention fully completed. The overall alpha was .80, with the values for all four subsamples (11–13 and 14–16 by gender) exceeding .70. There were significant differences in mean YP‐CORE scores by gender and age band, as well as distinct reliable change indices and clinically significant change cut‐off points. Conclusions These findings suggest that the YP‐CORE satisfies standard psychometric requirements for use as a routine outcome measure for young people. Its status as a free to use measure and the availability of an increasing number of translations makes the YP‐CORE a candidate outcome measure to be considered for routine services.