Yes; the real problem is when a proxy is substituted for what is really wanted - for example, when lines of code written is taken for a measure of how much usef

Yes; the real problem is when a proxy is substituted for what is really wanted - for example, when lines of code written is taken for a measure of how much usefulness has been created, or the percentage graduated is taken as a measure of the effectiveness of education. Proxies are not intrinsically bad, either, but they have to be difficult to achieve without also achieving what you really want - when this is not the case, making the proxy measurement a target motivates people to seek workarounds. Life expectancy might be a proxy, but it is a pretty good one.