Tools for monitoring and evaluation (M&E) should be consistent with those used for market assessment and intervention. Tools used earlier can provide evidence of overall market change, including specific dimensions changed by the intervention. A mix of methodologies is usually required to estimate the impact of an intervention. Quasi-experimental methods like comparative assessments of affected and control groups allow comparison of changes, while trend analysis compares changes in program and non-program areas. Qualitative methods help understand change processes and the role of the intervention alongside other factors.