Students with any legal training usually go ballistic when they find out that hearsay evidence is permissible in adjudications. It is largely excluded in the regular courts although there are exceptions like death-bed confessions. Hearsay evidence is indirect evidence. Someone told me that John Doe pulled the trigger for example. In regular court you have to find the someone to testify and be cross-examined, no one can simply relay the comment.
Hearsay evidence is fine in adjudication.
Consider that the issue in adjudication is usually not an eyewitness to an event or a crime. All the evidence is going to be largely opinion anyway, hearsay evidence can add to the process. There are restrictions on how decision makers can weigh hearsay evidence. It is definitely secondary evidence. But, my point is that its admissibility does not automatically corrupt the process.