"My take on it: let's say you tell the other per..."


by Alexei Andreev Dec 15 2016

My take on it: let's say you tell the other person you are running 10 minutes late. If you end up coming on time, then you get no social penalty for being not on-time (blue line at t="on time"), but you get a social penalty for being off your stated mark (red U at t="on time"). If you show up 10 minutes late, as you said you would, you get some social penalty for being late (blue line at t="10 mins late"), but a small amount of social penalty from red U (at t="10 mins late") because you actually showed up when you said you would (i.e. 10 minutes later). The reason it's small amount and not zero is because you are still 10 minutes late from the original time. If you said you would be 9 minutes later, then U would be closer to x-axis; at 5 minutes, it would be presumably half as high from the x-axis; and if you said you were running on-time and showed up on-time, then it would be tangent to x-axis (and t="on time" and t="reported ETA" would be the same).

One thing that's a bit misleading is that earlier in the post Paul says:

My total delay is the sum of two terms:
Error: How badly I messed up my departure time. If this term is large then it signals incompetence and disrespect.
Noise: How unlucky I got with respect to traffic (and other random factors). This doesn’t really signal much.

Error is the blue line. Noise is the red U, but he still counts that as social penalty. I guess it just doesn't factor into "signaling", meaning the other person might still be somewhat upset, but they won't take delay from noise as evidence about you.