"In an effort to apply more rigorous standards to National Intelligence Estimates, the National Intelligence Council includes explanations of the three levels of analytic confidence made in estimative statements.
High confidence generally indicates judgments based on high-quality information, and/or the nature of the issue makes it possible to render a solid judgment. A “high confidence” judgment is not a fact or a certainty, however, and still carries a risk of being wrong.
Moderate confidence generally means credibly sourced and plausible information, but not of sufficient quality or corroboration to warrant a higher level of confidence.
Low confidence generally means questionable or implausible information was used, the information is too fragmented or poorly corroborated to make solid analytic inferences, or significant concerns or problems with sources existed."
Actually, the FBI's "Moderate," confidence in the "Lab leak theory," does not warrant a "high level of confidence." All other US Agencies that have registered an opinion, give this a Low level of confidence. meaning "implausible information was used in its formulation." FYI.