I have measured my vocabulary of 20000+ with scallop words before (if only it were true). It's ridiculous for two reasons. First, this mode of word measurement does not require spelling, as long as you choose the corresponding definition, there will be some contingency; Second, scallops will give the word part of speech in their definitions. As long as they know the root, they can guess which one it is.
Measuring words in the field of happy words is relatively more objective. First of all, the parts of speech of the words selected for each question are basically the same, and even the length of the words is similar, so there is no possibility of choosing words according to their parts of speech. Secondly, some words it chooses are words with similar meanings. If you are not familiar with the meaning and usage of words, it is easy to get confused. This road is difficult for you.
The number of words is highly differentiated and objective, so I found that my vocabulary suddenly dropped to 10000 when I tested it with happy word field. Although it is not that high, it is at least a relatively objective vocabulary.