Actuarial involvement is required when both parametric and structural changes to the social security scheme are considered.

Changes in social security schemes are often triggered by concerns regarding future financial sustainability and current and future benefit adequacy. Reforms to programmes and the overall system may be parametric, i.e. mainly concerned with changes in eligibility criteria, benefit levels and the financing of the scheme. Structural reforms refer to more significant changes in the nature of benefits, including the introduction of new social insurance schemes, adopting new benefit provisions (e.g. covering new contingencies) or other changes to the nature of benefits (e.g. a move from defined benefit to defined contribution provision).