Effective Altruists would have us believe that applying metrics to philanthropy to measure the impact really began with this millennium, but it has been around for two centuries.
"Contrary to the impression given in many philanthropy blogs and in the pronouncements of contemporary movements such as “effective altruism,” providing evidence of philanthropic impact is not a new development. It has been at the center of the voluntary sector since its rise in the early nineteenth century.
"Evidence of the impact of the “philanthropic pound” was an essential part of charitable reporting to donors from the origin of the voluntary organization. The nineteenth century experienced a dramatic change in the way that charity was organized; in particular, it saw the decline of the traditional endowed charity set up by an individual in their will. The creation of an endowed charity allowed the individual philanthropist to have complete say over how his or her money was spent through the strict terms of the trust; this form of charity, however, required the philanthropist to have direct knowledge of both the geographical area and the problem that he or she wanted to alleviate. But by the nineteenth century it was difficult for the individual to have such direct knowledge of the diverse social problems being experienced in the rapidly expanding urban centers. This led to the development of a new form of collectivist charity: the voluntary organization. The crucial difference in this new form of charity was that it was entirely reliant upon the general public for its funding. The number of voluntary organizations rose spectacularly in the nineteenth century and this busy market had to compete for the public’s attention and money. It was therefore essential that they reported back to the public on how their funds were spent."--Sarah Flew, HistPhil