Hi,
I would like to confirm regarding the the last sentence. Which one is right?
" No recent data in X is available since the only study which was conducted to answer this question was in 1988"
"No recent data in Y is available since the only study which was conducted to answer this question in 1988"
I'd say #1 reflects your meaning best. Really, you should also say No recent data on X . Other possible prepositions include about/from.
I prefer to omit 'which was':
" No recent data on X is available since the only study conducted to answer this question was in 1988"
Best wishes, Clive