OCC2010 any change in June/July 2015?

I was computing month-to-month transitions between occupations (different digits as well as major and detailed groups) based on the harmonized OCC2010 variable and noticed a weird spike in June 2015. It jumps to around 7% while between 2005 and today it is usually around 2% or 3%. Also for the rest of the time range (even when there is a new occupation classification e.g. in Jan 2020) no such anomaly is visible. Is this a known issue/due to some reclassification or change in interviewing technique? Any help would be greatly appreciated.

I would attach the figure for the month-to-month transition rates for 10 major occupation groups but I’m not allowed to as a new user.

Can you provide a little more information about the discrepancy? You should be able to add an image to your post now, so adding that might help. If you’re having issues with this please email ipums@umn.edu.

I have a few immediate follow up questions: Is the rate that jumps to 7% the average monthly transition rate between any two major occupation groups, across all employed people? What coding of major occupations are you using? Which transition is anomalous, from May-June 2015 or June-July?