Assumptions of argument-based validation approach31
| Assumption | Data |
| Scoring: The items are understood, culturally relevant and acceptable, and staff are confident using the intake assessment tool. | RGG assessment Staff and client feedback on the survey (staff: how well did the client engage with this assessment? Clients: how easy or hard did you find this survey?) |
| Generalisation: Single sample of performance is indicative of all possible performances, that is, across conditions. | Test–retest reliability |
| Extrapolation: Scores on the intake assessment accurately reflect the construct being measured. | Assessment of internal consistency and construct and concurrent validity |
| Implication: the way in which the outcome of the intake assessment is used to inform decisions and actions | 6-month follow-up interview with young people and caregivers Case conference with staff involved in care |
RGG, research governance group.