Who and What Should Be Brought to the Hearing?
Naturally, the claimant and employer should attend the hearing. The claimant should attend because their right to benefits is in question; the employer should attend because their account may be charged for benefits paid as the result of the Administrative Law Judge's decision, or their liability as an employer may be affected by the decision. (Sometimes, a representative of the Agency will also attend the hearing). An Administrative Law Judge may also permit other observers at the hearing.
In deciding whom, if anyone, you should bring as a witness, it is important to keep in mind that the hearing operates within the general requirements of the rules of evidence, somewhat like a court, and that the Administrative Law Judge will not accept most hearsay testimony, that is, testimony not within the witness's own first hand knowledge.
This means that the Administrative Law Judge cannot permit a party or witness to answer a question by saying "I don't know what happened, but from what Joe tells me..." If "Joe" knows what happened, then "Joe" should have been brought to the hearing. Nobody else can testify as to what "Joe" would have said if he had been at the hearing. If, for example, a worker's attendance is at issue, the person with the most knowledge should appear as a witness to describe the claimant's attendance, and any warnings given.
In addition to bringing in witnesses with personal knowledge of the facts, you may wish to introduce documents to support their testimony. Documents include such things as attendance records, written warnings, dates of verbal warnings, layoff notices, and letters or other correspondence that bear on the case. However, the employer's keeper of business records should be present at the hearing to testify from them, and to testify that they are the actual records.
Another reason it is important to bring in witnesses, in addition to documents, is that only a person who is present at the hearing in person or by phone can be cross-examined by the other party. A notarized statement generally cannot, therefore, be brought to the hearing in place of a witness.