Table 1 Glossary of tools, terms and acronyms used in SSM

Rich picture – An illustrative picture of the structures, processes and actors involved in the problem situation and the interdependencies between these.

Purposeful activity model (PAM) – A conceptual model for one or more aspects of the problematical situation outlining a set of purposeful activities relevant to the situation. The model is a set of linked activities that together makes up a purposeful whole.

Root definition – A statement describing the human activity system to be modelled.

CATWOE –A mnemonic reminder to consider the following information about the human activity system:

Customers –The beneficiaries or victims affected by the problematical situation and the improvement intervention.

Actors –The individuals involved in the situation and in performing the improvement intervention.

Transformation – The change process.

Worldview – Underlying assumptions that makes the improvement intervention worthwhile and important.

Owners – The actors that are responsible for the improvement intervention and who decide whether it will be implemented or not.

Environmental constraints and enablers – The contextual factors that may influence the problematical situation and the improvement intervention.

The PQR-formula – A formula useful for defining the root definition. It is applied by answering the questions: what should be done (P), how it should be done (Q) and why it should be done (R).

Five E’s – Criteria for assessing the outcomes of the improvement intervention, including:

Efficacy – does the intervention produce the intended outcomes?

Efficiency – is the improvement being achieved with minimum use of resources?

Effectiveness – does the intervention help achieve some higher-level or longer-term aim?

Ethicality – is the intervention morally appropriate?

Elegance – is it an aesthetically pleasing intervention?