Quick question i need some help with

Quick question i need some help with

 “It’s not uncommon for marketers to identify an audience they want to reach only to discover once the campaign starts running that a very different group of people respond to the marketing materials”, it seems as if all the work done prior to launching the campaign was in vain since you might have a different group responding.

If the research was done properly and all the steps were followed how can a campaign fail?

complete answer orginal and plagerism free this is a MBA course so please be complete.

Ref:

Graham, S. (2013, November 19). The Business Journals. Retrieved March 06, 2016, from http://www.bizjournals.com/bizjournals/how-to/marketing/2013/11/5-steps-all-marketers-should-use-to.html?page=all