On that infamous study he used phone calls that had very strange results like doubling number of employees or going to entirely fulltime. When the study was redone with payroll reports, the results reversed - back to the start minimum wage effect.
So then they republished and it was like "well if we only look at this group and we take out these and adjust this number" they were able to recover their results but the data hacking was pretty terrible.
If you ate going to write a study like that, relying on phone data screams bias (and these were two economists that couldn't claim they didn't know better).
Citation, please? Card's matching analysis has been repeated many times (e.g., Dube, et al), and each time, they have found little demand elasticity for labor at the extremely low end.
So then they republished and it was like "well if we only look at this group and we take out these and adjust this number" they were able to recover their results but the data hacking was pretty terrible.
If you ate going to write a study like that, relying on phone data screams bias (and these were two economists that couldn't claim they didn't know better).