Cost of standing on 15/16 against 7

I notice quite a few 'ploppies' (as card counters like to call casual blackjack players, though I'm far more of a ploppy than a counter myself) like to stand on the worst stiff hands, 15 & 16, against a dealer's 7. I guess they think it's not worth it to risk busting against a relatively weak dealer upcard, which does have a certain logic to it, admittedly. Still, it does go against the common basic strategy, so what exactly is the cost of doing this? Is it significant, or is it as negligible as standing on 16 vs. 10?

Far more significant. On 15 (10,5) vs 7, the value of hitting is -0.368927, whereas the value of standing is -0.475708. The numbers for 16 are a bit closer together but similar.

The reason of course is if you make a hand of 17-21 against a 7 you are very likely to win (or push). Against a 10, you still lose a lot even if you make a hand of 17, 18, or 19, so hitting has less value.

A 7 is only a 'weak dealer card' if you have made a hand of 17-21. Then it's great. Otherwise, it busts only slightly more often than a 10. You should never stand on any stiff hand against it, it's not even near borderline.

Makes sense. Thanks.

It is a very common mistake. It just feels bad to bust when the dealer only has a 7. Wizard of Odds appendix 9 tells you all the expected values, so you can look up how much of a mistake it would be to go against strategy. However, the previous answer is correct. Standing on a dealer 7 is much worse than standing on a dealer 10 when you have a hard 16.