Contribution Tracing

Market registration copy.jpg

Contribution Tracing helps to assess our confidence in the emerging evidence for drawing valid conclusions about system change and impact in contexts where there are no (or insufficient) comparisons.

Contribution Tracing is a method we adopt in PIALA-based impact evaluation for assessing system change and impact of relatively small samples of cases (small n). The method combines Process Tracing and Contribution Analysis to reassemble the impact pathways through harvesting and linking evidence from many different inquiry streams that are mostly not comparable. It essentially involves the systematic collation and cross-checking of evidence using a causal process observation tool, and the scoring and improving of the strength of evidence for each step along the way, in order to establish confidence in the findings about systemic impact and contribution.


We understand a system as a collection of interconnected actors (animals, cells, humans, organisations…) that form a coherent whole and develop distinct patterns of behaviour and interactions following certain rules, values and beliefs. The system’s emergent structure co-evolves with the behaviours and interactions, and vice versa (i.e. “adaptation”).

This method is of great value for

  • Impact evaluation of innovative pilots of system change initiatives, of which there are only a few (cf. our work with Oxfam).

  • Independent review or assessment of contribution to impact and sustainability of an entire investment portfolio consisting of many different strands and mostly incomparable cases (cf. our work with IIED).

The method involves the following steps

Contribution Tracing takes similar steps as our Configurational Analysis method, but replaces most of its cross-case analysis (in Step 3) with a more in-depth and robust process tracing and contribution analysis process (in Step 2).