Needs Review vs Incomplete
What's the difference?
Actually, there is none. Both "needs review" and "incomplete" mean the same thing - that axe-core wasn't able to tell whether something was a violation or not with 100% certainty. Because of this, these results are recorded separately. The two names mean the same thing, that there may or not be an accessibility issue and more investigation is required. Because of axe-core's focus on zero false positives, we only include violations we're sure are actual violations.
If you're just beginning accessibility testing, or are working on a legacy site with many issues, it is likely better to work through the known violations first. If you have access to a digital accessibility expert, it would be best to consult them on the needs review/incomplete issues before ignoring or tackling any of them. Remember, just because it's marked as review/incomplete doesn't mean it's a violation.