• by Tameka Kee , March 26, 2008

While paid search has been lauded as one of the most quantifiable marketing channels, advertisers--particularly large brands and Fortune 500 companies--have found it more difficult to calculate a precise ROI for their organic search efforts.

But a new study from Covario links various search engine optimization (SEO) tactics to specific changes in organic search rankings. The interactive marketing technology firm has applied the findings to its Organic Search Insight tool--giving clients like P&G a better way to gauge the value of their SEO spending.

Effective SEO involves making changes to and monitoring the placement of Web site content like editorial copy, keywords, inbound links and graphics to gain better visibility through organic rankings on the search engines. For a CPG giant like P&G that means managing content across multiple brands like Folgers and Pampers in multiple languages --with total Web page volume well in the millions. Having an automated way to optimize changes that generate favorable results (or flag tweaks that could cause rankings drops) becomes a priority, so Covario launched a seven-month study in March 2007 to come up with statistical proof of efficacy.

Over 300 brands participated in the study, which found that the big three engines (Google, Yahoo and MSN) all react very differently to SEO techniques. For example, Google is twice as sensitive to technical issues (like having a Flash-based site or a site that takes too long to load) as MSN--meaning that making adjustments to technical areas would likely affect rankings on Google more than they would affect them on MSN. Meanwhile, Yahoo and MSN were noticeably more sensitive (25%) to content changes than Google.

Covario used Organic Search Insight to crawl the participants' Web sites on a bimonthly basis, performing 46 checks on each page of each site. According to Craig Macdonald, vice president of product management and marketing at Covario, the data is roughly 65% accountable for future variability in rankings--with the remaining 35% related to factors (mostly around link strategy) that the engines keep under wraps.

"Based on our analysis of this data, we feel comfortable saying that Covario Organic Search Insight has detected key patterns that will have a large impact on the organic search process for large advertisers," Macdonald said.

Armed with this knowledge, advertisers using the tool can make changes to their Web sites with end goals for ranking on each engine in mind. "With a statistical model, a project manager or director can say 'we need $100,000 to spend on optimizing, and here's the model for how we're going to spend it. This is how Google is going to react, how Yahoo will react, and how the resulting rankings will affect click-through rates, conversions and ultimately sales," Macdonald said.