The old joke goes that if you train your employees too well, they’ll leave—but don’t train them at all and, lucky you, they stay. We might update the joke with a perverse punchline—train your employees the traditional way and watch the best of them leave and the rest of them flounder.

It’s no secret that post-recession, top performers are on the move. By relying on ineffective legacy training programs, large organizations are providing elite learners with just enough resources to get ahead, leaving those with less learning savvy behind. Yet large organizations across the globe continue to groom their top talent only to see them go, neglecting the rest of their employees and leaving a lot of talent on the table.

If you don’t provide ample development to the rest of your workforce, you risk being left with B and C players only. When top performers at your company are tapped for bigger and better opportunities, your talent will be out the door just the same as if you didn’t invest in them at all.

Meanwhile, the largest cohort in the American workforce will be waiting in the wings to fill those seats. Training and development is the most desired job perk among millennials, 5 percent more popular than cash and three times as popular as a 401(k). Conscious of the professional growth they need in order to advance their careers, young professionals won’t be attracted to your organization unless you provide them with unique development opportunities that actually work.

Employees in the digital economy are distinguished not by what they know, but by how fluently they meet changing demands on the job. Today’s knowledge workers have to use rapidly evolving technology and discern useful knowledge from a constant torrent of information. Both abilities require continuous refinement, which requires a faculty for learning that is, a skill. Like any skill, learning doesn’t distribute evenly among the workforce. An outdated training approach only serves individuals to whom learning comes naturally.

Here’s how to accommodate your entire workforce, from laggards to learning masters:

  1. Provide learners with resources that actually work: Abandon traditional training and development formats in which too much, mostly inert information is delivered all at once, out of context, and far from the point of application. Instead, mix job aids and other just-in-time resources with training grounded in spaced, varied and interleaved practice.
  2. Use technology that makes learning feel easy: It’s hard to learn how to learn. Use strategies that make serious learning feel simple and convenient. Microlearning, for example, uses short bursts of content to bring information painlessly to learners of all strengths and abilities. From onboarding through succession, employees should feel like they have relevant learning resources available to them at all times.
  3. Build metacognitive skills: Rote training is obsolete in an environment of spreading automation and rapidly evolving technology. Each learner’s higher-level functions empower them to adapt to changing tools and “know what they don’t know.” In a world rife with distraction, it doesn’t hurt to develop the skill of attention management, helping people focus on the details most relevant to their work and goals.

Training is only useful as long as the thing you’ve been trained to do hasn’t changed. Development, meanwhile, is a long-term way to build the skills necessary for a workforce to become good at their jobs. And though being good at your job could give you reason to leave, it sure feels good to stay.