Short answer. Substantial evidence — the least demanding standard the Rules define. Under Rule 133, Section 6, in cases filed before administrative or quasi-judicial bodies, a fact may be deemed established if supported by that amount of relevant evidence which a reasonable mind might accept as adequate to justify a conclusion.
What the law says
In cases filed before administrative or quasi-judicial bodies, a fact may be deemed established if it is supported by substantial evidence, or that amount of relevant evidence which a reasonable mind might accept as adequate to justify a conclusion.
Rule 133, Section 6 — Substantial evidence. Read the full provision →
Where the standard applies
The standard belongs to a specific arena: In cases filed before administrative or quasi-judicial bodies. That is the world of proceedings decided outside the regular courts — disciplinary cases against employees and professionals, regulatory complaints, and the many disputes the law assigns to agencies and tribunals rather than judges. In that arena, Section 6 says, a fact may be deemed established if it is supported by substantial evidence. The question in such a case is never whether guilt was proved beyond doubt; it is whether this defined quantum was met.
What 'substantial' actually means
The section defines its own term: substantial evidence is that amount of relevant evidence which a reasonable mind might accept as adequate to justify a conclusion. Every word narrows it. The evidence must be relevant — actually bearing on the fact to be proved. The measure is a reasonable mind — not the most suspicious reader nor the most forgiving. And the evidence must be adequate to justify a conclusion — enough to support the finding as a rational matter, even if another mind might reasonably have concluded otherwise. It is a test of quality and sufficiency, not of volume.
What it is not
Two boundaries keep the standard honest. It sits below the standards the same Rule prescribes for court cases — less demanding than preponderance of evidence in civil actions, and far below proof beyond reasonable doubt in criminal ones — which is why conduct that fails as a crime can still cost a licence or a job. But it is not nothing: bare suspicion, speculation and unsupported accusation are not relevant evidence a reasonable mind could accept as adequate. A decision resting on conjecture fails this section even in the administrative arena.
Litigating under it
If you are answering an administrative complaint, take the low threshold seriously: the other side does not need a courtroom-grade case, so meeting their evidence squarely — with your own documents, records and sworn accounts — matters more than pointing at what they lack. If you are the one complaining, the section is a reminder that even the gentlest standard still demands evidence: identify each fact you must establish and match it with something relevant a reasonable mind can hold. Either way, cases under this section are usually won on paper assembled early.