[stephencanon]

Not really surprising at all. A huge amount of selection has already taken place by the time you get to the interview, and most of that selections is based either on grades or on other metrics that measure similar traits. The “low-GPA” individuals who get an interview are therefore very different from the general population of “low-GPA” individuals, and one expects there to be little or no correlation between GPA and success (if anything, I would expect negative correlation, as low-GPA individuals who get interviews will have something else going on that got them there).

This is almost exactly the same effect as the fact that SATs do not predict college GPA. SAT scores are used as one of the major factors for admission to colleges; having separated the students into cohorts based (partially) on SAT, it is completely expected that SAT scores have minimal correlation with grades assigned within each cohort.

[rlanday]

The sorting continues in college; SAT scores are most predictive for the first year, before less-capable students switch out of the hard majors. My guess is that nearly all of the engineers Google hires score very highly, and in that sense the SAT is indeed predictive of success there (since you can take it in middle/high school), but they might have determined that discriminating on the high end between differences of <1 SD (about the validity between retakes) might not tell them much.