I have a corpora of queries and answers where the queries are the title of different documents and the answers are a short description of them. E.g:
Title: African Civilian Deaths
Description: How many civilian non-combatants have been killed in the various civil wars in Africa?
I have tried to build a DSSM model to compute the cosine similarity between a given title and the queries so I could print out the one with bigger similarity expecting to be the right one. For instance, when writing "African Civilian Deaths" I was expecting to get the description between the top 10 answers, which didn't get to happen being in the 45th place.
As I didn't succeed doing this I was wondering how could I do it using tf-idf. I know how to compute the relevance of each word in my documents and so on but I don't really know how to make the comparison... Or how to say that this description corresponds to the title. Therefore, my question is how could I use tf-idf for comparing a query and an answer to see how close they are. I want the real question to be at least in the top 10 of most similar answers.