A patent filed by Google [patft.uspto.gov
...] in Nov 2011 suggests that your pages CTR while displayed in serps creates a score and impacts the movement over time effect of the page in rankings.
2. The method of claim 1, where determining the amount or rate that the document moves in search result rankings includes: determining a number of positions that the document moves in the search result rankings, and where generating the score for the document includes generating the score based on the determined number of positions that the document moves in the search result rankings.
The patent titled "Document scoring based on query analysis" further ties into the spam detection effect of another patent discussed here [webmasterworld.com
...] in that there is a rate over time effect...
11. The memory device of claim 10, further comprising: one or more instructions to employ measures to prevent the rank of the document from changing at more than a predetermined rate.
The result may be that if your page receives a low ranking on initial indexing that there will be a time delay, and struggle, to make it rise to the top. CTR plays a pivotal role in the rise or fall of the document, depending on how heavily weighted this ranking method is, and its likely that other factors like backpaging does too.
Is it time to rethink the importance of those webmaster tools metrics that suggest a low CTR from search?