Who do O/O use for the random drug testing program ?

I really don't know procedures of how the selections are made. I only was guessing that random selection would indicate that from one drawing from the pool of Y drivers they need to select X drivers. So with Y getting bigger and X staying the same, or increasing but at slower pace than Y, the chances to be selected are decreasing.
You could call OOIDA and there is a nice lady who doesn't mind to spend some time with you on the phone to talk over these things. I remember when I called her, she said that the chances of being selected with their large consortium population was smaller than elsewhere.
In the last year or two, FMCSA pressed consortiums for more selections, so naturally chances of someone getting selected increased too.

 

In your example I believe you're not accounting for Z

Y = total number of drivers
X = drivers who need to test
Z = drivers who don't need to test
Y = X+Z
X = Y * 50%
Z = Y * 50%
That means for every two drivers who walk through the door of the consortium they both have an equal chance of becoming X or Z. No matter how many drivers walk through the door, each driver has a 50/50 chance of becoming X.

Thanks for the OOIDA suggestion.

 

Every pool is required by law to test minimum 50% members for drugs and 10% for alcohol ( same person can be tested for both ), but it can also test more depend from consortium. Pool can choose how often it will draw for test, but need to meet minimum by end of year

 

So if the pool is 1000 drivers and 500 of those will be tested then my chance of selection for the drug test is 1/500.
If it is 2000 drivers than it is 1/1000.
The bigger it gets the less chances for selection. Or else I am missing something embarrassingly.
Ha ha ha ...

Wait a minute:
Let's see first my selection chance is 50% or 1/2
Then the next selection is 0. 2% or 1/500
So after multiplying it is back to 1/1000

What the heck am I missing?

 

%50 seems high......

 

Out of 1000 drivers 50% must be selected no matter what...
Then from that half e.i. 500 drivers one driver is selected, assuming that only one draw is made after the 500 were selected already. So what are the chances of getting selected in %?
500/1000*1/500 = 1/1000???!!!
Hmmm

 

I must always be in a big pool cause I never get selected.

 

Seriously, we have 100 drivers and they by law must select half to take random. That's 50% chance.
So it shouldn't matter of what size the pool is. I proved myself wrong thinking that the size of the pool mattered. Since they always need at least half, the probability must be always no less than 50%.
If the pool size is bigger it means that consortium must perform more draws.

 

I think it's determined by the previous years failure rate so for example if the line in the sand is 10% then when more than 10% of the randoms test positive it jumps to 50% and when it stays below 10% it drops to 25%. I'm pretty sure my numbers are incorrect but the idea is correct.

 

Initially I had to pause because I was coming at it from the same angle.