But major can make a much larger difference in some cases. While 2017 L&S CS graduates at UCB tended to have very successful first job searches, 2017 biology graduates at UCB tended to have significantly less successful first job searches:
https://career.berkeley.edu/sites/default/files/pdf/Survey/2017IntBio.pdf https://career.berkeley.edu/sites/default/files/pdf/Survey/2017MCB.pdf