When companies do everything correctly in the sales hiring process, they:

• get the job spec right
• write a killer ad to attract the candidates who meet the spec
• use the Internet effectively to source the right candidates
• use recruiters that "get it" and will actually find qualified candidates
• use a predictive sales specific assessment early in the process
• conduct a short phone conversation with recommended candidates to further filter out
• conduct an effective first interview with candidates who pass the first three hurdles
• identify the candidates that will succeed
• conduct an effective final interview on the candidates they wish to hire
• conduct an effective 90-day on-boarding process

...and they are still vulnerable to salespeople leaving within the first 9 months.  Why?

The reasons fall into 4 basic categories:

1. Sales Management
2. Culture
3. Expectations
4. It's Them

When it's sales management, the reasons usually can be traced to managers that don't manage full time, managers who aren't fully engaged with their salespeople, managers who aren't effective at sales coaching, managers who are shit-heads, and phantom managers.  In other words, salespeople are hired where there is no sales manager.

When it's the culture, it tends to be more about not putting salespeople in a position to succeed.  It could be the overall company attitude, product, support or technical people, the way the company does things - its policies and guidelines, top management, lack of sales support, compensation, or a myriad of other things that drive salespeople crazy.

When it's about expectations, it could relate to compensation, sales cycle, degree of difficulty, performance requirements, the time frame, leads, prospecting, competition, resistance, and more.  It could be that either no expectations, unreasonable expectations, or inaccurate expectations were set, all making it very easy for a salesperson to become frustrated, disappointed and discouraged.  

When it's about them, they usually failed.  They could have personal issues, psychological problems and/or distractions preventing them from consistently putting forth the time, energy, effort, discipline and skill required.

It's not enough to do everything right from a selection standpoint.  You must also make sure that your culture, sales management and expectations all support the first year efforts of salespeople you put a lot of effort into hiring.