Can a Sales Personality Test or DiSC® Properly Assess Sales Candidates

Ed Marsh | Apr 8, 2022

Tl;dr - Companies that improve strategy and marketing may find little impact on revenue. It's common to discover in retrospect that legacy sales teams are poorly suited to execute in today's environment. But simply hiring new talent often compounds the problem. Rigorous sales force testing and candidate assessments are necessary but misunderstood. Poorly informed practitioners and improperly applied assessments are detrimental.

Tests and Assessments Can Help Us Learn and Grow

I often speak with folks who, like me, are fans of assessments. You may also be intrigued by insights tools can help you gather to help you improve your individual performance and interactions with others.

I enjoy a range of assessment tools from the Peloton FTP test and careful daily habit tracking, to behavioral/personality tests like the Herrmann Whole Brain® Thinking (that I've written about before) and Hogan. Ray Dalio's description of how his team used the Myers-Briggs Type Indicator (MBTI®) in Principals - especially his team playing cards - was fascinating1.

So it's natural that people who value assessments to improve their own performance look for tools to help optimize their company's talent and performance. Hiring for sales is a natural next step because it's so different from hiring for other roles. After all, they're setting out to "sell" you. We're poorly equipped to react as research by Andy Miller2 shows.

Traditional hiring tools have shockingly low predictive accuracy!

  • resumes - 18%
  • traditional interviews - 18%
  • behavioral assessments - 20%
  • personality assessments - 22%
  • reference checks - 23%

At the end of the day, whether you think you have a consistent, scientific, and accurate method or not, you're probably relying on "gut feeling."

How many other half-million dollar decisions do you routinely make on "gut feeling?"

So we need a better way. But what about the data above? Most assessments are only marginally better than resumes? Let's dig in, and start by understanding assessment types.

Ipsative vs. Normative Methodologies

The assessments that I listed above cover a wide range. Beyond the obvious difference (fitness, discipline, work styles), there's a technical distinction. The FTP and behavioral tracking are "normative" tests; that is they are built on an empirical measure. This could be books read/year, pulse rate, average cycling output in watts, number of days of journaling/week, etc.

Herrmann and Hogan are different. They are "ipsative." What's that mean? "Ipsative tests compare a person with himself, and so highlight his (relative) strengths and weaknesses."3 In other words, they provide a framework for me to compare myself today to myself of weeks, months, or years ago. They are not absolute measures that are appropriate for comparing me to you today.

Assessments that compare us to ourselves can be used for self-development and blending teams to bring complementary approaches together precisely as Dalio described using Myers-Briggs.

DiSC-behavioral-assessments-are-not-recommended-for-pre-employment-screening-1This is an important distinction to understand. Ipsative tools are neither designed nor appropriate, to select one sales candidate over another.

In fact, although many people rely on the DiSC and Extended DiSC for sales employment pre-screening, the company itself states clearly that they "are not recommended for pre-employment screening."4 

We shouldn't be surprised that they're not predictive. In fact, the only thing that merits surprise is that there are "experts" who advocate using the assessments in ways that even the licensors discourage!

Further, some labor law and DEI experts note that using an ipsative test for pre-employment screening is legally indefensible because of the inherent lack of predictive power in the methodology. Employers who rely on this type of assessment likely create liability exposure for their companies to suits from candidates who respond to unfavorable hiring decisions with legal action.

Broad Assessment Categories

Professional assessment tools normally fall into one of four general categories.

  1. Personality assessments - tend to measure how people socially
  2. Behavioral style assessments - seek to understand how people communicate and work
  3. Aptitude assessments - quantify knowledge around particular subjects
  4. Psychological assessments - used to gauge emotional stability for medical purposes

The first two can be helpful to anticipate how someone can fit in a group. They are not designed to determine the expertise with which someone will execute specific vocational requirements. Assessments in the aptitude category may predict certain skills for certain roles, and for most businesses, psychological assessments aren't relevant to hiring decisions.

Let's look at an intentionally contrived example comparing one and two vs. three.

What's the most important set of criteria for hiring a controller:

  • A - the fact that (s)he goes to church regularly and therefore you impute a higher level of moral rectitude
  • B - their ability to close the books on time and accurately?

Certainly, you want a trustworthy controller. But we all understand that the belief that regular church attendance is an assurance of propriety is our own projection and not a valid predictor of a lower likelihood of fraud. That's a reckless inference from their reported behavior.

On the other hand, their (in)ability to maintain accurate books is absolute. The books are correct, or they are not.

So when it comes to hiring a controller the important set of criteria is "B" - their ability to execute the task precisely.

That makes sense. What doesn't make sense, however, is our tendency to ignore what's so obvious in other roles when it comes to hiring for sales.

Why do we rely on a gut feeling, inadequately substantiated by a non-predictive personality assessment, to predict sales effectiveness? It's kind of silly when you lay it out....

So what's better?

A Sales Assessment Needs to Measure Who WILL Succeed

What does a salesperson need to succeed? 

Of course, there are attributes like intelligence, creativity, facility with language and communications, and work ethic.

But attributes aren't enough.

They also need technical skills; how to ask the right kind of questions, in the right way, to elicit important information. This helps them establish credibility at the same time they uncover compelling reasons to buy.

But those attributes and technical skills aren't enough!

Successful salespeople must actually use them. So we must understand what limiting beliefs and weaknesses would prevent them from doing so.

After all, if they don't have specific technical sales skills, at best they'll ramp up slowly and require lots of training. At worst, they'll cost you money directly and indirectly in a non-performing territory.

But if they have attributes and skills and won't use them because of limiting beliefs or performance weaknesses, it's worse than not having them. Now it's not enough to teach them, you have to overcome deeply held beliefs about what they can/can't do. Non-performing salespeople in this category are common. And they become a project. Don't you have enough of those already?

But we're not done yet!

Even having required attributes and skills free from weakness isn't necessarily enough!!

Those skills and attributes also must match your specific market environment. Sales cycle, decision-maker seniority, transaction size, the intensity of competition, and other factors shape your market environment. That set of conditions dictates the normative strength that's required for a given level of performance. 

Calling on office managers of $5MM companies to sell $500/month payroll services is vastly different than calling on division presidents of a multinational to sell $10MM systems that impact their ability to make the product on which their brand is built.

Even a simple difference - is your product "nice to have" or "must have" completely changes the difficulty of the sales role.

So a sales candidate assessment - at least if you're genuinely interested in one that has significant predictive validity for sales effectiveness - must:

  • measure aptitude, and
  • identify the strength (or absence) of specific sales skills, and
  • uncover inhibiting and supporting factors, and
  • measure these against normative standards with predictive validity, and
  • consider the aggregate result in the context of your market environment

The facts that someone likes talking to strangers at a cocktail party, or is impatient in achieving milestones are unrelated to the simple outcome that's important to you.

Even more than whether they "can" sell - whether they WILL sell.

Comparing Tools to Make the Right Choice for Your Business

There are lots of enthusiastic marketing and sales claims, and committed practitioners for every assessment on the market.

And the assessments themselves have often adapted their outputs for different use cases and adopted language that sounds very pertinent to sales.

"Prospecting", "Hunter", and "Qualifying" are terms you may see in assessments. Since you're relying on these to make ≈$500K decisions, be sure to dig into what components they include, and how they quantify those. My prediction is that you'll realize they're sort of like hiring the self-proclaimed churchgoer as the controller because you hope they won't defraud you.

Many people mistakenly believe that familiar tools will help you legally (when challenged), accurately and consistently select sales candidates who will succeed. As Miller's research finds, that's simply incorrect.

So how can you sort through the fluff to discover which actually will? (See the ironic challenge here? We're trying to figure out which assessments REALLY will help you select capable salespeople in order to hire the ones who REALLY will sell!!) 

Here's a good place to start. Request and review the "Technical Manual" for any assessment tool. Although they make for rather dry reading, the technical manual will provide background on the methodology and importantly, provide a statistical finding of predictive validity. If your consultant isn't familiar with the technical manual or hesitates to provide it, that's an indicator that you probably need to dig more aggressively.

And you need to use the right assessment for the right purpose. Once you've used an effective and predictive sales or sales management assessment as part of a rigorous hiring process, you might want additional insights. So a cocktail of assessments can be helpful, and personality and behavioral type assessments may be perfect complements at this point.

For instance, if you have a pod or team arrangement (marketing, marketing ops, sales ops and sales working in a team on complex ABM type sales) you might evaluate behavioral styles to optimize team composition. BUT, that's a secondary requirement to assessing candidates to figure out who will sell.

Know What Your Testing and Use the Right Tools

If you're trying to evaluate sales candidates to understand not only who CAN sell, but the few who actually WILL sell, then you must use tools that are capable of doing so.

Unfortunately, that puts the burden on you to understand nuances in methodology, employment law, and statistical predictive validity. 

1 - Although he's subsequently replaced that with the "PrinciplesYou" assessment he's created with Adam Grant
2 - Andy Miller, The Science of Hiring Quota Busting Sales Teams 
3 - StatisticsHowTo on Ipsative tests
4 - DiSC® profiles..."are not recommenced for pre-employment screening."