For those who don’t know Google Correlate it’s a wonderful tool. Given a temporal or spatial data, Google Correlate determines which queries at Google best mimic the data. It allows for automated query selection across millions of candidate queries for any temporal or spatial pattern of interest. Similar to Trends and Insights for Search, Google Correlate is an online system and can surface its results in real time.
For example let’s say you want to find what queries are more correlated to mortgage applications in America. Then, you just need to upload the data and Google Correlate will find what query is most correlated to it. According to this, the search volume of “refinancing calculator” has a very high correlation with the actual value of mortgage applications.