Yale Research Initiative on Innovation and Scale

The science of evaluating small-scale programs is well developed. However, complexities can arise when we want to know the impact of large scale programs that operate across entire districts, states, or countries:

1. Political Economy Effects | Scaling a program can affect the political behavior of policymakers, politicians, and voters, with implications for the effectiveness of the program.
    
2. Spillover Effects | In addition to the individuals directly targeted by the program, programs affect non-beneficiaries through channels such as social networks or changes in prices.
    
3. Evidence Aggregation, External Validity, and Generalizability | Initial research may show that an intervention is promising. However, outside its original evaluation context, an intervention may have more null, nuanced, or negative results.
    
4. Macro, Growth, and Welfare Effects |The changes in individual behavior caused by a program can, at scale, have larger impacts on the overall economy.

This project will involve reviewing the literature and writing on the above-listed topics as well as several promising programs that are candidates for large-scale implementation.