Ask HN: Formula for better measuring improvements in SERP position over time?
Our startup is constantly focused on improving our SERP position for key, transactional terms. However, measuring progress on a weekly basis across thousands of terms can be a challenge. Moving from SERP position 45 to 40 is way easier than moving from 6 to 1, and this makes it challenging to determine holistically how much we are improving on a weekly basis across thousands of terms.
One can imagine that the SERP position vs. difficulty graph looks like 1/x where the y-axis is difficulty and the x-axis is SERP position. Thus, measuring improvement would involve summing 1/$current_serp_position - 1/$previous_serp_position for each term. This is obviously very crude, has anyone come up with a more refined and accurate way to measure this?
It's a bit noisier than pure SERP position, but tracking actual weekly traffic from transactional keywords should naturally normalize the value of SERP gains across keywords of differing popularity and rank.
There is a whole literature about it. Check http://en.wikipedia.org/wiki/Discounted_Cumulative_Gain
Not entirely sure what you're asking here, but if you're trying to measure keyword difficulty, keyword rank, and their intersection, SEOMoz has tools w/ APIs for this.