[bsder]

Mostly, no. Nobody except for expensive precision resistor companies are actually measuring resistors more than statistically.

The resistors are manufactured so that they are "guaranteed by manufacturing" such that the outliers are 1%, 5%, 10%, etc. And they do statistical checks on batches, but not really looking for the 10% outlier (which is stupendously rare and very difficult to catch) but looking for slight drifts off nominal (which are much easier to spot) which would result in more outliers than expected.

As such, if you measure resistors, you tend to find that you get really close to nominal--much closer than you would expect for 10%, say. Resistors are so cheap that binning simply doesn't make economic sense.

[LeifCarrotson]

Is this how LEDs are binned as well, or are they powering each node on the wafer before packaging? They're orders of magnitude more expensive than resistors, so I figure they might...

There are all kinds of crazy parameter variations in optoelectronics. I understand that resistors are really close to nominal because the manufacturer's ability to tune the process controls are so much better than the standard 5% and 10% bins, but it seems that LED manufacturing is way more difficult and they can't always tune the process to get exactly what they want.

[mastax]

I saw a video from the WS2812 factory and from what I remember all of the LEDs were tested individually on the die before assembly. I don’t know if that’s typical but those are pretty cheap for what they are.

[anticensor]

They should still bin, so that each individual resistor gets the highest price possible by the virtue of its classification, even if the binning is costly.

[mgsouth]

Not if the additional cost is more than the additional revenue.

Let's assume that without binning you get 20% over cost of manufacturing. If it costs 5% more to bin-check all resistors, and you wind up selling 1% of them for an additional 100% mark-up:

                     No bin          Bin
    Cost to mfg:     $ 1.00       $ 1.00
    Cost to bin:                     .05
                     ------       ------
    Total cost       $ 1.00       $ 1.05

    Base price       $ 1.20       $ 1.188   (99% sold at base)
    Premium price      0.00       $ 0.022   (1% sold at un-binned cost x 2.2)
                     ------       ------
    Total revenue    $ 1.20       $ 1.21
                     ======       ======
    Profit           $ 0.20       $ 0.16

[bsder]

SMT resistors in bulk are a fraction of a penny.

Tester time FAR outweighs any gain you could get by binning.