To answer this question, you have to understand three parts of the equation. The first part has to do with the natural optimism of hiring managers. The second has to do with the relatively weak pool of candidates hiring managers have to choose from. And, the third has to do with hiring processes that don’t account for parts one and two.

Here are some stats to consider:

Natural Optimism: 94% of sales managers are optimistic about their salespeople, while only around 50% of salespeople have been able to hit quota any year since 2008. Too often, the optimism cultivated by sales managers is not based upon data, predictive investments or measurable outcomes, but rather some feeling or hope that things will somehow get better.

Weak Candidate Pool: Only 28% of all salespeople are competent enough to earn an interview, while the vast majority of hiring managers have no objective way to measure sales competency during the hiring process. If hiring managers had these tools, they would be able to ignore the 72% of salespeople who clog their candidate pipeline and put their selection process and sales team at risk.

Hiring Process: 46% to 50% of new hires fail within 18 months and most sales leaders live with that number because they can’t see a way to improve their hiring and on-boarding process. When hiring processes improve, so does the effectiveness of sales leaders and the longevity of their salespeople. The right hiring process will ensure 9 of 10 new sales hires perform among the top half of their new sales team within just 12 months, and sales managers will be encouraged to improve accountability and their investment in coaching and developing team members.

Every marginal salesperson added to your sales team makes your business weaker. Like an eagle plucking feathers from its own wings as it tries to gain altitude, when hiring managers throw marginal new hires against the wall to see if one sticks, growth becomes more difficult and less predictable.

The goal of any sustainable sales organization must be the adoption of a proven hiring process, built to source, select and retain team members who demonstrate they CAN and WILL succeed within their first 90-days on the job.