Circular evidence — how the case's strands depend on each other
Prosecution claim
The Crown's case at trial was presented as the mutually-corroborating weight of many distinct strands of evidence: medical causation, statistical pattern, handwritten notes, Facebook searches, handover sheets, search history. The jury was asked to find that the combined weight satisfied the criminal standard of proof.
Counter-evidence
Independent review identifies that the strands are not independent but structurally circular. Dr Evans's causation opinion rests on the premise that a cluster requires a criminal explanation. The shift-rota chart was constructed by selecting events partly because Letby was there. Dr Bohin's second-opinion evidence worked within the methodological frame Evans had established. The handwritten notes were produced after the consultant-team suspicion had been communicated to her. The Facebook-search curated subset was selected in retrospect from a much larger denominator. The handover sheets were retained under the NHS confidentiality framework the same way many nurses retained theirs. Each strand, examined individually, does not establish what the Crown claimed; the cumulative argument only works if the strands are treated as mutually corroborating independent evidence, which on structural analysis they are not.
If each strand depends on the others for its meaning, the combined weight is not the sum of independent evidences. It is the same proposition repeated in several registers.
What the jury heard
The Crown's closing speech presented the strands as mutually corroborating. The jury was not systematically walked through the circularity analysis independent experts have since applied.
What the Panel says
The Panel's case-by-case medical review treats each count on its own medical merits without relying on the pattern argument. That approach — each count independently — produces the conclusion that medical evidence of deliberate harm is absent in every case reviewed.
What independent experts add
- The Evans causation opinion was instructed on the basis of the cluster having been framed as a possible criminal pattern.
- The shift-rota chart's 25 events were selected partly because Letby was there.
- The Bohin second-opinion worked within the Evans methodological frame.
- The Post-it notes were written after consultants had told Letby they believed she was responsible.
- The Facebook-search curated subset is a selection from a multi-year denominator not shown to the jury.
- The handover sheets' retention reflects NHS confidentiality policy, not distinctive behaviour.
- When each strand is examined on its own, the evidential weight is much less than the cumulative argument suggested.