I know that this question is hard to answer, but I was wondering how you would determine if a statistical technique was in current use, or if it had a heyday a couple of decades ago but it's either been superseded by newer techniques or perhaps it was even proven to be inadequate and abandoned?
For example, I was looking at a time series with R and stumbled onto the EMD package (Empirical Mode Decomposition). The technique looks like interesting, but as I google around, it seems that it never really became popular. Was it confined to the neural research community? Did wavelets prove to be superior? Did it prove to be a bit hard to interpret?
Perhaps there can be no definitive answer, but perhaps there are signs you look for?