The ****Meaningful Measurement (MEANS) Lab**** is based on three pillars: **Pillar 1: Meaning making in self-report measurement** When people score self-report measures, they are asked to translate their experiences into numbers. This mixed methods study systematically explores *how* respondents interpret items and translate experiences into numerical scores; with focus on meaningfulness of scores as part of a clinical narrative. **Pillar 2: Response shifts in measurement of mental health change** When people change their interpretation of their mental health complaints throughout therapy, their interpretation of items in self-report measures might change as well. Such change in scale interpretation is called a *Response Shift* and threatens the validity of ‘gold standard’ pre-to-post symptom level comparisons (RCT) and routine measurement (ROM, ESM/EMA). This research line conducts qualitative analysis of Response Shifts in psychotherapy research. Rather than a threat to validity, the occurrence of Response Shifts is proposed as a new and clinically relevant indicator of outcome, as it signals therapeutic change. **Pillar 3: Validity in the action of mental health measurement** Provided that self-report measurement contains meaning (pillar 1) and is prone to change through treatment (pillar 2), it is vital for the *users* of self-report data (researchers, clinicians) to validate their interpretation based on the actual meaning-making by the respondent. This requires validation in the action of administration – beyond the psychometric validation of the measure – in which the respondent and the administrator both play an active and continuous role. This research line involves all stakeholders in mental health measurement to develop a tool for meaningful validation-in-action, that fosters asking validating questions rather than presupposing answers. The full **Research Program** of the Meaningful Measurement (MEANS) Lab is [outlined here][1] [1]: https://osf.io/tu7rx