Most guidelines for choosing the dev set size also apply to the training dev set.

Google

A training dev set is a separate subset split from the available training data that the algorithm does not train on. It is drawn from the same distribution as the training set and only needs to be large enough to evaluate and track learning progress.

Training Dev Set

Machine Learning Yearning, a free ebook from Andrew Ng, teaches you how to structure Machine Learning projects.
https://www.deeplearning.ai/machine-learning-yearning/

Note: The content of the book is aligned with the Coursera Deeplearning.ai specialization.  https://www.deeplearning.ai/deep-learning-specialization/ 

Machine Learning Yearning (Deeplearning.ai)

With separate training, training dev, dev, and test sets, one can evaluate training error on the training set, generalization to new data drawn from the training-set distribution on the training dev set, and performance on the target task using the dev and/or test sets.

Learn Before

Related