Beck has several tiers.
Tier 1. About 5K words, Known to native speakers. Sad, funny, blue, old, etc
Tier 2. About 7K words. These we need to learn. adept, adopt, conundrum, remorse. These are basically words with a shade of difference meaning than a tier 1 word. Example: "sad" is a tier 1 word but "forlorn", "regretful", "melancholy", and "depressed" would be tier 2. (source: John & Beck Videos)
Tier 3. About 10K more words of domain specific and academic vocabulary.
Tier 4. There's also another 300K of very specialized vocabulary.
Sadly, many schools have students from language deprived backgrounds who need help mastering even the basic 5K of Tier 1 words.
VocabularySpellingCity is doing this research review on vocabulary so that we fully understnad which words lists are worth studying and in which way. Of course, the gola is tention and our key is to avoid the weekly cycle with cramming, to support a multiweek cycle of encounters with the words which include 12-1 word encounters of a large variety of types. And to truly deal with nuance and context, not just to oversimplify...