Self-assessment is so messy that lists like this are just misleading. Among other issues, many of the criteria for "expert" sound more like the criteria for "l

Self-assessment is so messy that lists like this are just misleading. Among other issues, many of the criteria for "expert" sound more like the criteria for "library developer". Many conventionally-expert application developers and data scientists would smartly not use those features and may self-assess themselves out of the category for lack of active practice. Meanwhile, too many conventionally-junior developers would sophomorically insist that they can and should use them and self-assess themselves as experts.