How costly is it to obtain labeled data? [D]

Doing my masters thesis in Active Learning. A key point in the literature is active learning may be useful in situations where there’s lots of unlabeled data, and the cost associated with labeling is high, so active learning can effectively same time and effort in labeling, if the model can “choose” a subset of samples which are the most “informative” and then these can be labeled.

However, I kinda realized, as much as this active learning stuff is interesting and …

active learning cost data key labeling literature machinelearning thesis