The GPG perspective has contributed to a large number of new programs. However, some caveats are in order. Providing an adequate supply of a GPG requires spending more than would have been spent in the absence of collective action, i.e. "additionality." The additionality debate is complex, and involves at least three questions: -At the individual country level, we may ask whether international assistance for production of GPGs in Country X reduced (or, in development parlance "crowded out") Country X's government spending for production of GPGs. Since most of the countries in question are very poor and local needs take clear precedence over global ones, it is probably safe to answer this question in the negative.