Hello, I seem to have a sample ratio mismatch in one of our recent tests. We have run multiple tests both using the JS SDK (visual editor) and making codebased changes using PHP SDK. Previous tests have run as expected with an even split and even current tests are running as expected apart from this one. The test has been running for nearly a month and has never evened out. Is there a way for us to identify why this particular test has an issue? We also have no multiple exposure warnings just to rule that out. Thank you

SRM errors can be caused by a few things: 1. Did you change the split at all during the running of the experiment? 2. Do you have any caching? Sometimes caching can cause an increase in one variant

Thanks Graham, we haven’t changed the split at any point. We do have multiple caching layers so it could be this. For this test and future tests is there anything we can do to point more towards the variant with significantly less without having to change the split?

no, you shouldn't need to (nor should you) adjust the split to make the traffic 'more equal'

Ok thanks for clarifying. What would be the best way of trying to debug the issue? Like I say we have run multiple tests through growthbook and this is the first of its kind we’ve experienced. Worth mentioning this is a redirect test.

you can try to find a user who was assigned A but should have been assigned B

Ok and how would I know which variant the user was meant to be assigned if it’s a random allocation?

we used deterministic hashing

Ok thank you we will investigate and see if we can find any evidence. Thank you