Most businesses understand the importance of training, which is why U.K. companies spend an average of £1,068 per employee on learning and development, according to Bersin’s 2016 U.K. corporate learning factbook. However, many businesses still do not measure their ROI, and those that do often use the wrong metrics.

For example, the average business may deduce that an increase in sales means that their sales training is going well, when in reality, many factors may have contributed. This mistake could lead to ignoring shortcomings of the training program. Ultimately, ignoring your training in this way can cost you in overall revenue.

Return on Investment

The biggest problem companies have when it comes to measuring their sales training ROI is that they look at the wrong metrics. While an increase in sales is obviously good news, it is not necessarily something that can be attributed to training. Similarly, there may be areas of improvement that take time to show up in pure sales success.

A company that doesn’t truly know its ROI cannot even begin to resolve problems with a training program. These problems may have far-reaching consequences. While it is important to monitor sales and similar metrics, the simplest way to measure ROI is to divide your team into two groups:

“Compare the performance of one sales group (that gets trained) against the performance of a second sales group (that does not get trained),” writes Geoffrey James in Selling Power Magazine. “The presence of the untrained group (aka the ‘control’) filters out other factors that might be influencing sales, because both groups are operating under similar … conditions.”

Information Retention

Another common mistake businesses make with their training programs is failing to pay enough attention to the follow-up. Studies show that ignoring the reinforcement stage of the training process can be extremely costly, because it means that much of the money spent on training is actually wasted.

Indeed, research by Huthwaite Inc. shows that salespeople lose around 87 percent of the information they acquired through training within one month if it is not reinforced in the workplace. To put that in perspective, it means for every £1,000 spent, £870 produces no tangible long-term benefit.

For this reason, your sales manager training should emphasize the role that leaders have in coaching sales staff and reinforcing what they learn in training. When reps are encouraged to put their new skills into action quickly, learning retention rates drastically improve.

Impact on Your Revenue

The key benefit of a good training program is that it will help to improve the skills of your team, leading to greater sales and higher revenue. Therefore, the main consequence of neglecting to evaluate your sales rep and sales manager training is a poor-quality program that fails to develop these skills.

A study by CSO Insights found that the impact of a good training program on a business was significant in several areas. Organizations with excellent training programs had higher win rates, more employees who achieved quota and lower staff turnover than those with poor training.

Ultimately, failing to pay the right level of attention to your training can hurt your revenue. Coupled with lack of retention, this means that ignoring your training is a costly mistake.

Monika Götzmann is the EMEA marketing director of Miller Heiman Group, a global sales training and customer experience company specializing in providing exceptional sales management training and helping organizations develop business strategies to achieve sales success.