Actually oftentimes it isn't worth taking a scout for stealth reduction.
If you have 4 ships against stealth 5, odds are that 1.333 of your ships will see the target.
If you have 3 ships and 1 scout, if the scout succeeds then 1.5 of your ships will see the target, if the scout fails then 1 will see it. So weighted average, 1.25 of your ships will see the target.
You're worse off for taking the scout.
With 2 scouts it gets worse...
If you have 4 ships against stealth 5, 1.333 will see the target.
If you have 2 ships and 2 scouts, if the scout succeeds then 1 ships will see the target, if the scout fails then 0.666 will see. Weighted average, 0.833 of your ships will see the target.
This ignores the scout's firepower, but that is usually fairly small. The main benefit from the scout's firepower would be the further stealth reduction from having shot the target already, but since your scout should be 20"+ away you'll be on 6's, so not likely to happen.
The more ships you have, the better a scout's value is... with 5 ships it is pretty much even, with 6 you see a slight benefit of taking a scout. But, they are pretty much over-rated IMO! Apart from Vree, ISA, Gaim and Psi Corps, and anything CQ5+ in a campaign... more likely to succeed in reducing stealth, makes more benefit. And Leshath of course is awesome.
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