There are a number of methods designed to measure advertising effectiveness. One approach is to conduct surveys both pre and post the campaign and compare the results of the surveys to ascertain it's effectiveness. Sometimes participants are shown clips of TV ads and asked if they recognise them...

Methods like this have been used for a long time, but often they rely on the accuracy of participants memories.

The problem with this is that memories (not just advertising, in general) are often malleable or just inaccurate. One interesting example of the malleability of memory is Braun, Ellis and Loftus's (2002) experiment Make My Memory: How Advertising Can Change Our Memories of the Past. As such, the recall of an advert may not be the best starting point to measure the effectiveness of a campaign.

One method which gets helps round this problem of recall, and could be used in conjunction with other methods or as cheap (if not as in-depth) alternative to an expensive ad tracking study is Google Analytics. You can use Google Analytics to measure the actions taken for any campaign (off line or online) which has an online destination or goal. It's particularly useful if you're simply interested in how many conversions are directly linked to a campaign opposed to things like raising brand awareness.

I thought about writing up a guide on how to use Google Analytics to track ad's but fortunately there a number already out there:

http://blog.mediacatalyst.com/index.php?/archives/102-Google-Analytics-A...