Analyzing the ROI Formula - Part 2

This post continues our discussion about measuring the performance of marketing, including the use of marketing return on investment (ROI).

As I have already noted, the basic ROI formula is:

ROI = (Gain from Investment-Cost of Investment) / Cost of Investment

Therefore, marketing ROI is calculated using two factors - the gain or incremental "profit" produced by a marketing campaign or program and the cost of that campaign or program.  My last post discussed the Gain from Investment component of the ROI formula.  This post will focus on the Cost of Investment component of the formula and discuss some of the issues this component presents when ROI is used to measure marketing.

Cost of Investment is the total cost of the marketing campaign or program whose ROI is being measured.  At first glance, this can appear to be an easy determination to make, and in some cases it will be.  For example, if you outsource all of the work required to develop and execute a particular marketing campaign, the investment in that campaign will be easy to identify.

In other cases, however, the issue becomes more complex.  For example, if creative elements are developed that will be used in multiple marketing campaigns or programs, how should these creative development expenses be assigned to the multiple marketing efforts?  What if you don't know how many times a creative element will be used?  Should the labor costs of marketing department staff personnel be treated as marketing overhead or assigned to specific marketing campaigns or programs?

The most important principle to use when assigning expenses to specific marketing campaigns or programs is that cost assignments should always be based on real-world cause-and-effect relationships.  In other words, the marketing campaign or function whose ROI is being measured must be the "cause" of the cost or expense.

As noted earlier, this principle can be fairly easy to apply in some cases, such as when expenses are incurred to pay outside contractors (agencies, designers, printers, etc.) for specific work on a specific project.  Internal marketing department expenses can be more difficult to address.  For example, if you employ graphic designers, it is appropriate to assign their labor-related costs to the projects they work on.  On the other hand, it may not be possible to assign the labor costs of higher-level marketing managers who perform more general marketing activities.  Often, these costs cannot be logically assigned to specific marketing campaigns and should be treated as overhead expenses.

Assigning costs to marketing campaigns and programs can become relatively complex, and marketers may need to obtain help from financial professionals in performing these assignments.  Assigning costs accurately is essential to producing accurate ROI calculations.