Is Google Trends Reliable?
A burning question for every research source out there is how reliable it is, and some searches on Google Trends make me question some of its data. Look at the graph below for search volume on "divorce," "funeral," "marriage," and "birth." Outside of a couple spikes relating to news events (gay marriage, the Pope's funeral, etc), the patterns are remarkably similar. Is there some reason for the similarities, or are there problems with the data? I'm investigating further, but looking into the Yahoo Buzz Index and Microsoft adCenter Labs, the pattern isn't repeated there, and in fact varies greatly. For instance, with adCenter, searches for divorce far outnumber searches for marriage.
Click the chart below for a better view:
Colleague Andrew Chang had a great idea, causing even more question into Google Trends. See what happens when you add Britney - it's way too similar:
