Anyone that has ever managed people (or that has worked in a team) knows how frustrating/exhausting it can be to have a poor performer in the midst. If that person(s) goes unaddressed, it's horrendous for morale and productivity. If they get addressed, but unsuccessfully, it can be horrible for morale and productivity.

And in some companies, removing an underperformer can be more difficult than saying no to a Reese's Chocolate-Peanut Butter Egg.

So what to do?

Research shows the vast majority of managers believe poor performers underperform due to one of three things:

a) They assume the poor performer isn't capable of doing great work,

b) They assume a major character flaw (laziness, lack of ambition, etc.), or (relatedly),

c) They assume the poor performer doesn't care about doing the job right.

Research among underperformers shows a much more complex view of the world, however.

Here are 10 real reasons poor performers don't do what they're supposed to:

1. They think they're already doing it

2. They think something else is more important

3. They don't know why they should do it

4. There's no positive consequence for doing it

5. They don't know what they're supposed to do

6. They're rewarded in some way for not doing it

7. They don't know how to do it

8. They don't know when to do it

9. They think someone else should be doing it

10. They don't like doing the work they're doing

Given this, first, it's critical to assume that people want to shine, not shirk. No one wakes up in the morning and says, "I can't wait to get to work today and completely under deliver".

OK, other than the New York Knicks.

Next, it's helpful to bucket the above list into aptitude and attitude issues to determine the necessary course of action.

For example, suppose an employee is consistently producing inaccurate or untimely reports (important reports).

Poor performance could be coming from several different underlying attitude issues. Referring to the list, perhaps the underperformer feels that the work is simply uninteresting, he doesn't know why he's doing it, or she doesn't feel she specifically should be doing the work.

He might think something else is more important, he won't be rewarded for the work, or that he might be rewarded in some way for actually not doing the work. The result is a seemingly nonchalant set of attitudes and behaviors.

If a base of trust has been established with underperformers, you can quickly find the root cause of the issue and develop a plan to address.

You can reframe tasks for employees, show them the importance of the reports, indicate how they'll be rewarded for doing the work well, explain how they're uniquely suited to do it, and discuss the undesired behaviors behind the attitude to yield something more productive.

Now let's say that the poor performance is aptitude-based. Again, using the list above, suppose the issue is that the underperformer simply has never gotten training on the reports so they don't actually know what they're supposed to do, how or when to do it, or they actually think they're already doing it correctly.

This scenario requires some fundamental skill building to enable people to do the work with success.

The point is that behaviors and outcomes that have attitudinal issues at their core create one path of actions. Those that have a deficient skill set at the core require another. Pinpoint which of the two is at work and adjust your approach accordingly.