Hi Vijay,
In my view these are terminologies used to classify people in terms of their performance ratings. I will attempt to explain you the same -
Work horse - These are people/employees who works hard and diligently often taking extra efforts and initiatives (swift like a horse)
Deadwood - These are people performing at the lowest performance level, often are considered as poor performers (dead trees and branches)
Stars - These are employees who are the best performers and are often ready to move up to the next level of hierarchy
Problem children - These are people who are better then the deadwood in terms of performance but are yet to go a long way to reach the desired performance level
In other words, these can be explained in terms of performance ratings as follows -
Stars - Rating 1 - Significantly and Consistently exceeds requirements
Workhorse - Rating 2 - Consistently meets expectations
Problem Children - Rating 3 - Partially meets expectations
Deadwood - Rating 4 - Does not meet expectations
I hope Vijay, I have been able to answer your question to some extent.
Regards,
Prachi