How do you measure the return on investment of an offline marketing campaign?

Before starting an offline campaign, you must first look into what you have currently, what are the stats of your current market, your business stats to be exact. Then after launching the campaign, monitor your numbers closely, if your numbers went up or down, that will define how effective your offline campaign is.

well it's an open question and I think there are many successes or failures to be measured in a marketing campaign. For an integrated marketing communication campaign every point of contact with consumers should have a unique objective that will add to the sum of the IMC components to generate success, hence ROI.

Think about a campaign ran by Dunkin Donuts in Seoul years ago. After a while the coffee-like odor diffused in buses would certainly have lost the initial effect on commuters; so the measure is inherent to the time the campaign was run. But wait! are they measuring coffee sales or donuts sales or other pastries sold by the coffee shop, or volume of orders at a certain point in time?

This is where each piece of communication plays a role in the marketing mix and measure should be based on specific intentions i.e. driving more traffic to the coffee shop, increasing brand recognition and adoption, promotional sales and repeat purchase e.g. customer loyalty and so on. From my experience, measure is dependent on objectives and fortunately we have the web today to isolate every marketing intent/action so measure could be done precisely, thanks to analytics!      

By analyzing reports from each promotion (SWOT) at end of it's period to evaluate success / failure of each promotion of sale along with normal sale.

Hi Dana. Interesting question. Something the marketing companies have been wrestling with for eons. And perhaps one of the top reasons why advertisers felt safer in the arms of the new online phenomenon which could actually show & tell the success or failure of a particular piece of communication by quoting actual results & hard numbers. It's a different story that very same reason is now being checked for veracity and accuracy in various courts of law across USA. But back to your question. One effective way of actually measuring the yield of an offline campaign is 'planting unique response triggers in every piece of communication which can then be measured independently.' I agree it's a very short answer - but you didn't expect me to tell you everything, did ya...?!! Have a great weekend.