Research at the SRI has investigated optimisation methodologies for accelerated environmental tests such as Highly Accelerated Life Tests (HALT) or Highly Accelerated Stress Screens (HASS). Multi-scale thermal, mechanical and hygro-thermal responses of representative, generic systems have been measured, and ‘compact’ computational models have been formulated to determine the local conditions (temperature, humidity and so on) within such systems. In particular, the research has addressed: product robustness; acceleration factors to facilitate quantitative inferences from life tests; and screen strength metrics.