Tracking offline conversions has been a challenge for businesses for years. As long as the Internet has been widely used to drive business, tracking online marketing efforts to offline purchases has been no easy feat, but while there is no silver bullet approach, rest assured, there are ways to make it easier.

For brick and mortar businesses, obviously a large percentage of their conversions take place offline, despite an amplified online presence and rigorous online marketing tactics. As local search continues to sprout new innovations, one can only assume that the web will continue to drive offline purchases better and better. With some consumers going to their smartphones more than their PCs for online shopping research, businesses are seeing more mobile customers who may be more apt to swing by a physical location while they're on the go.

KeyRelevance President Christine Churchill once wrote, "Measuring offline conversions and proving on paper that the online marketing triggered the offline conversion is difficult, because you can’t often directly measure the process from start to conversion." Therein lies the problem. Out in San Diego at the Online Marketing Summit this week, WebProNews spoke with Salesforce's Global Head of Search, Lauren Vaccarello about this subject.

Google and comScore once conducted a study, which showed that 63% of consumers who conduct product searches online buy the same items offline. It's been a while, and that number may have changed by now, but what hasn't changed is the fact that people are still finding products online and buying them offline.

At an SMX Advanced conference, she recommended in-store surveys to find out the ways people are arriving at their purchases. In addition, online coupons and offer codes can be tracked offline. At that same conference, Ryan Gibson of the Rimm-Kaufman Group suggested introducing "actions of value" on a site, such as allowing people to order a catalog or sign up for emails.  Specifically, ad-spend, return on ad spend return on investment, and cost per order/acquisition) are all things to consider tracking. Rich Devine, ZAAZ's director of search also recommended assigning dollar values to things other than the main conversion. 

When it comes down to it, without a way to track an offline sale, it's going to be difficult to tell how effective your online marketing efforts are.