Research aim: to emphasize that a suitable research concept is required to analyze “the extent to which a certain care concept counteracts subjectively perceived stressors during everyday care and support”. Methods used: summative evaluation design – more precisely, a semi-experimental design with a control group and an experimental group, collecting data at two waves (“before and after” measurements). It permits the simultaneous evaluation of the experimental group (in which a new concept is introduced) in one or more care homes and the control group (in which the specific concept is not implemented) in comparable care homes. Changes over time can thus be studied under controlled conditions. Lessons learned: the implementation of a care concept in nursing homes depends on the people involved, from the management to the caregivers. Even if the background conditions (e.g., legal regulations) and the characteristics of the home or the organization running it (e.g., mission statements) are identical, the way in which this type of concept is dealt with personally evidently plays a key role in its effect, or at least this is the only explanation for the identified differences. Moreover, the initial starting point is important when measuring the effect of a new concept. The level of improvement (as in a positive effect) will be minimal when a high level of caregiver motivation, or of nursing and care, is already reached, before a new concept is introduced.