I had a professor in college whose lesson on measurement I will never forget.
He began by posing the question "Are fat people lazy?" After several minutes of emotionally charged debate within the class, when it seemed pretty obvious that there was no possible way to answer the question with any consensus, he gave us this script to follow:
1. Define "fat." We could use weight/height ratios; body mass index; body fat content; or one of several other ways. But until we could agree on what "fat" meant, we would not be able to answer the question. This discussion revealed some significant differences of opinion in the class about the definition of a simple word: "fat."
2. Define "lazy." This simple word proved even more difficult to define. Once again, there were several ways we could approach this, ranging from levels of exercise weekly to work habits to overreliance on modern conveniences. It was much more challenging to arrive at practical consensus over the definition of "lazy," and many in the group had to eventually accept a definition they didn't particularly feel comfortable with in the spirit of moving forward.
3. Define the standard of proof. The question "Are fat people lazy?" doesn't explicitly have a standard. We could imply the question would require a finding that a simple majority of "fat" people are "lazy," or we could adopt a much higher standard (e.g., 99%) of proof. Ultimately, the group settled on 90% as the standard.
4. Design a means of observing if the question is true. Collect data. Conduct research. Test the premise that 90% of people who qualified as "fat" did indeed exhibit "lazy" tendencies. (Easier said than done, I know, but gimme a break -- only so much I can explain in 800 words or less).
The relevance to marketing? What if you were to apply the same lens to the question "Is our marketing cost-effective?" First, you'd realize that there was little possibility to achieve consensus in an unstructured, opinion-driven dialogue amongst any number of key stakeholders. Next, you'd follow the process to define what you meant by "marketing" and by "cost-effective." Then you'd try to agree on the standard of proof. And finally, you'd design experiments and research to see if the hypothesis (e.g., "Our marketing is cost-effective") is actually true.
If your marketing measurements are stalled, you may need to reframe the approach. Too often we in marketing assume that simple terms like "marketing" and "cost-effective" are universally understood. They are, but not with a sufficient degree of commonality. Which is exactly where the "political" arguments begin to form.
This process is designed to extract all the opinion- and experience-driven biases out into the open and reconcile them BEFORE the measurement work actually starts. As a result, even imperfect measurement methods can be embraced and acted upon with confidence to make decisions about seemingly difficult questions.
And in case you were wondering, there is no credible evidence that in general above-average body mass is caused by "laziness."