THE COBRA EFFECT AS A METHODOLOGICAL WARNING

Once a measure becomes a target, it ceases to be a good measure. This principle — expressed variously through Goodhart's Law, Campbell's Law, and the parable of the Cobra Effect — has profound implications for how development and humanitarian programmes are designed, monitored, and evaluated. This handbook argues that metric-driven adaptation is not a peripheral risk but a structural feature of any incentive-linked measurement system. It develops a theoretically grounded, practically operational framework for M&E design that takes this risk seriously: mapping incentive architectures before finalising indicators, balancing throughput measures with inclusion and integrity counterweights, building verification into routine monitoring, tracking behavioural adaptation directly, and applying reflexive scrutiny to the evaluation apparatus itself. Seven operational tools are provided for immediate application in programme design, inception planning, and evaluation briefing contexts.