Over at her blog, Notorious PhD responds to a comment in which a reader asks whether it's the case that in graduate school earning "anything less than an A- is disaster." Notorious PhD says that for students working toward a terminal master's degree, "a couple of B's aren't going to kill you." But for those who seek admittance to a PhD program, "a B … can hurt your chances. … That B may mean that your margin for error has disappeared." However, blogger Prodigal Academic says that, in her experience, "grades are actually a poor predictor of success. ... I've found that many students with high GPAs are not necessarily good at research."
Still, grad students who eventually wish to enroll in a PhD program,m but are making B's in their master's training would be best to "make an appointment with the professor or the grad advisor to determine how you can do better," Notorious PhD says. Students, she says, are "usually worried that we're not doing well enough. And the culture of grad school replicates this." But in the end, "if you can be satisfied with a B (which is, by most objective standards, a perfectly respectable grade), then you have a healthier ego than most academics," Notorious PhD says.