Every SEO initiative is tied directly into Google Analytics and more sophisticated tools like SEM Rush.  Using these tools, each month analytical reports are created for law firm SEO clients that identify site traffic, top landing pages, top search queries, length of time people are spending on the site, and specific search engine rankings based on specific keywords and phrases.
The nice thing about a law firm SEO strategy is that there are measurable ways in which we show clients the ROI they are generating. We can also tell which sites are referring to our website, and whether people are viewing our websites on a mobile device or desktop.