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  • Common Math Mistakes That PR People Make


    4.5 min to read by AirPR Team
    Published on May 13, 2016

    Let’s be honest. The typical PR person has an aversion to math.

    Couple that with the fact that the PR industry has historically lacked the type of quantitative performance data that’s usually available to marketing teams, and you’re left with a large group of professional communicators who are prevented from tapping into insights that could help them perform better in their roles.

    Here are some examples of common number-blunders. If you’re making these mistakes, you’re downplaying the role of PR:

    Math Mistake #1: The Law of Large Numbers

    For data to be statistically relevant, you need a sufficiently large sample size for your estimates to have reliable predictive value. Pitching survey data is a common area where this issue comes into play. For example, Penny the PR manager has a great idea for an internal communications survey about job satisfaction, but journalists are unlikely to justify using her data because the sample is simply not big enough to return meaningful results.

    Math Mistake #2: Reporting % Growth

    One of the most egregious positioning errors is when small companies pitch extremely high percentages as impressive growth rates. This often causes the adverse effect: instead of “Whoa, Company X crushed it last year!” the reader thinks: “Whoa, I had no idea Company X was that small to begin with.”

    If Sammy’s String Cheese had $2,500 in sales in 2014 and $70,000 in sales in 2015, it would be mathematically true to say Sammy’s String Cheese grew 2700% despite a relatively small increase in revenue of just $67,500. When a bigger company goes from 10MM to 20MM, the growth figure is 100% but revenue is actually up by 10MM. Business-minded people get the nuances of this and gawk at those who don’t.

    Math Mistake #3: Reporting % Change

    A similar error occurs when calculating % change. If your employee count grows from 100 to 400 in a year, many people would eyeball that as 400% growth when it’s really 300% growth or 3x plus your original number. You can’t include your starting point as part of any growth you report. That’s just not how it works, folks.

    Math Mistake #4: Believing in Advertising Value Equivalency (AVE)

    Since much of the influence of PR is felt indirectly, the industry has struggled to develop effective proxy measurements to connect PR success to revenue-related figures. Sadly, AVE (also known as ACE or Advertising Cost Equivalency) is a proxy measurement that is prone to lead people astray.

    For marketers, it’s much easier to arrive at reliable figures for return on investment. If you spent $100K on AdWords and sold $150K of product to people who clicked on the ads and converted, then your campaign returned 1.5x. Since most marketing measurement is based on link tracking, earned media, which rarely features links, is especially difficult to accurately measure in this way. (Only ~15% of all earned media includes backlinks.) Without links, there’s no way to determine direct causation.

    Using AVE to assert that the cash value of earned media is proportional to the amount of money a brand would have paid in order to purchase advertising is incorrect for so many reasons. What you pay for something is not necessarily what it’s worth.

    Math Mistake #5: Overvaluing Impressions

    Impressions sound the most impressive, but while representing the total number of people who could have seen a given piece of content does provide some insight into your ability to reach large numbers of people, impressions do not tell you whether or not you’ve accomplished a business goal.

    You can use one gallon of water or 10 gallons of water to wash your hands after handling bacon. Though 100 gallons sounds like it could give you a better chance of accomplishing your goal of cleaning your hands, if you don’t have any soap, more water isn’t going to help much. If your approach is ineffective, no amount of impressions will drive increased performance.

    What you need to know is what works. Even if the number of PR-driven conversions is just 100, therein lies the answer to improving PR performance. What content, publications, or messages were most successful? That’s the important question. Not, “How can I reach the largest number of people with a message I can’t be certain is influencing anyone?”

    No one’s perfect, and we all have room to grow in certain areas of our professions. But if you’re a PR pro, you don’t have to fall victim to the embarrassingly common math mistakes outlined above. Rest assured that there are tools today that can help you effectively measure the worth of PR, and remember that it’s all about asking the right questions.

    How are you ensuring that your efforts are impactful?

    Join the conversation!