I would really have liked to see them check whether the gender-blinding actually worked. Even if someone's voice is modulated, they may have gendered behavior patterns that could influence someone's performance ratings. I wouldn't be surprised if I could guess the gender of a voice-modulated person pretty accurately from other cues.
To combat this, they could have asked the interviewer during the performance assessment whether they thought the applicant was definitely male/probably male/unsure/probably female/definitely female. Then you could use voice modulation as an instrument for perceived gender and get a better estimate of the true effect of perceived gender when controlling for actual gender.
Hope they do something like that for the next round of experiments!
To combat this, they could have asked the interviewer during the performance assessment whether they thought the applicant was definitely male/probably male/unsure/probably female/definitely female. Then you could use voice modulation as an instrument for perceived gender and get a better estimate of the true effect of perceived gender when controlling for actual gender.
Hope they do something like that for the next round of experiments!