[AnimalMuppet]

If you fire the 20 younger engineers, you're also firing the people who will be the "10 older engineers" in a decade. You're killing the future.

But firing the 10 older engineers, you may be killing the present. Even with no bias, it's not easy to know what the right answer is.

[dj-wonk]

You've made two good points. I would suggest the next step is to synthesize them. As with many things, moderation is important. A strategy that balances the two downsides is probably better.

[rosege]

Odds are that each group has a bit of dead wood so taking some from each group would be best - identifying that is the harder part for those several rungs higher

[dunpeal]

As if in today's job market, keeping any engineer provides any sort of guarantee that the engineer will stay with the company "for the future".

Most likely he'll stay until he gets a better offer (if he's a good performer) or gets laid off in a couple of years (if he's a poor performer).

[chii]

you'd fire 5 older engineers, and 10 young ones.

[zentiggr]

Fire 5 old and 10 young? QED