So I was thinking

Hey There,  Recently, I've been working on a big keyword project for a software company, and it got me thinking... I'm in the process of defining a traffic timeline with estimates to make sure we hit some of the campaign's core KPI's, which are all measures of month over month organic traffic growth. So while out on my bike this past weekend, in the midst of the usual fight with exhaustion that comes around the 20 mile mark, I started running through measures of keyword difficulty. In terms of rank potential, I was just rolling over the usual suspects; domain authority, trust flow, citation flow, number of linking root domains, and link acquisition rate... Then it hit me. There's no metric for measuring something we're all aware of; SERP volatility. Back in school while studying finance we learned about beta, or the measure of a stock's volatility - and while we're all aware of the differences between some SERP's 'rate of change' versus others - there's no established metric to measure this; there's no keyword beta. So per the usual, I've begun scraping craploads of data on this from all the indexes I have access to and trying to discern some correlations. Ideally I'll be able to come up with a few "categories" of SERP volatility that I'll be able to fit a sample population of keywords into. The practical application of all of this is, which I've been personally battling for about the last 12 months, there are some damned SERP's that have rankings that just don't seem to move... No matter how much better your content, architecture, links, everything - regardless of what you throw at moving up into top positions for some keywords - some SERP's just seem stubborn. And I want to know why, well, which. Which SERP's have such low volatility that there lack of fluctuation needs to be considered when assessing rank potential. So I'm going to try to find out - but I wanted to share this concept with you, since most of you are as in-tuned with SEO as I am (if not more) in case I'm barking up the wrong tree, or in case I missed something and am trying to reinvent a metric that already exists, but I simply didn't know about. If so, I'd really like to know about it.  In general, I'd be curious what you think about this idea of trying to compute an individual keyword's beta, based on a measure of SERP volatility. If you have a few minutes, and this sounds at all interesting, please give me a quick reply and let me know; it could be as simple as just replying with "yes." I would really appreciate it. Thanks for your time, Nick P.s. - My new keyword intelligence tool, Sentinel, that automatically builds your keyword matrix is launching this Thursday. If you want to be the first to get access (at no cost) sign up here. Crap! If you leave you will lose access to exclusive updates (like this one) and free stuff I send only to my email list, plus I'll miss you - but if you must go, you can here.