Analyzing the ROI Formula - Part 1

This is the third in a series of articles about measuring the performance of marketing, including the use of marketing return on investment (ROI).  In my last post, I described the basic concept of ROI and discussed how ROI has been used to measure many types of business performance.  Beginning with this post, I'll discuss each component of the basic ROI formula and explore some the the issues that each component presents when ROI is used to measure marketing.

The basic ROI formula is:

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

So, the ROI formula contains three components:

• Gain from Investment
• Cost of Investment
• Time - Although the formula doesn't expressly contain a "time" value, ROI is always measured for a defined period of time.

This post will focus on the Gain from Investment component of the formula, and this component presents two basic issues.  First, how should Gain from Investment be defined?  And second, how should ROI be calculated when the Gain from Investment is produced by more than one marketing campaign or program?

For ROI purposes, the best definition of Gain from Investment is the incremental contribution margin produced by the marketing function or by a marketing campaign or program.  One of the biggest mistakes that I still see some marketers make is to use incremental sales (revenues) to calculate marketing ROI.

To understand why this mistake distorts ROI, remember that most marketing programs are designed to increase sales volume either by acquiring new customers or by increasing sales to existing customers.  But increases in sales volume are not free - there is always an associated cost of producing and delivering the additional products or services.  Therefore, if incremental sales are used to measure ROI, the ROI will be overstated.

Using contribution margin solves this problem by taking costs into account.  Contribution margin is defined as sales minus variable costs.  Variable costs are costs that the company will not incur if the additional sales are not made.  Therefore, incremental contribution margin is a measure of the "net new revenues" produced by a marketing program.

The second major issue presented by the Gain from Investment component of the ROI formula is how to address situations where the Gain may have been produced by more than one marketing campaign or program.  This situation is not at all uncommon in B2B companies where each prospect may be "touched" by several marketing programs over the course of his/her buying cycle. 

Some companies deal with issue by assigning all of the incremental contribution margin earned from a prospect to the marketing program that generated the first "inquiry" from that prospect.  Others assign all of the incremental margin to the program that "touched" the prospect last (just before the purchase).  It should be obvious that this first touch/last touch approach will often produce a distorted picture of marketing ROI if a prospect has had several interactions with your company.

Some companies attempt to eliminate this distortion by allocating the Gain to all of the marketing programs that "touched" the prospect.  But what percentage of the Gain do you assign to each program?  Allocating the Gain equally to all of the marketing programs may not reflect which of the programs were truly influential in the purchase decision and which ones weren't.  Unless you have some way of knowing how much influence each program actually had in driving the purchase decision, the allocations are arbitrary, and the resulting ROI measurement is likely to be inaccurate.

This allocation issue presents one of the most serious challenges in measuring marketing ROI accurately, especially when we attempt to measure marketing ROI at a very grandular level.  The difficulty of using ROI in this way suggests that there may be a better approach, and I'll have more to say about that in a later post.

The Basic Idea of Return on Investment

As I wrote earlier, return on investment has become the "gold standard" for measuring the performance of marketing.  Return on investment is now used to measure both the performance of the overall marketing function and the performance of individual marketing activities and programs.

In addition to measuring past performance, marketers are using ROI estimates and forecasts to make decisions about future marketing programs and to allocate marketing budgets.  Therefore, ROI is playing a significant role in determining how marketing wll be done.

The basic idea of ROI is easy to understand.  Investopedia.com defines return on investment as:  "A performance measure used to evaluate the efficiency of an investment or to compare the efficiency of a number of investments.  To calculate ROI, the benefit (return) of an investment is divided by the cost of the investment; the return is expressed as a percentage or a ratio."

The basic ROI formula is:

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

For example, suppose that you purchase 100 shares of stock for $10 per share.  One year later, you sell the stock for $11 per share.  Your annual ROI for this investment would be 10%, calculated as follows:

ROI = ($1,100 - $1,000) / $1,000
           $100 / $1,000
           10%

ROI has been used to measure the performance of companies and business units for over eighty years.  ROI estimates have also been used to evaluate major capital investments for decades.  More recently, ROI has been used to measure the benefits provided by everything from process improvement projects to employee training programs.  All things considered, ROI (or one of the variations of ROI) has become the most prevalent measure of financial performance used in business today.

It's only natural, therefore, to use ROI to evaluate the performance of marketing activities and programs.  CEO's and CFO's are rightfully demanding proof that their "investments" in marketing are producing real financial benefits, and they view ROI as a proven method for measuring those benefits.

So, if you're a marketer today, you need to be ready to measure and/or estimate the ROI of your activities and programs, or you need to be prepared to show why a different metric should be used in lieu of ROI.

In my next post, I'll take a closer look at the "return" component of the ROI formula and explore some of the issues that arise when ROI is used to measure marketing.