We read a large amount of commentary on Witness and Bible Student history. Many of those who write about these groups lack understanding of evidentiary value.
The best evidence is contemporary to the events. But not all contemporary documents have the same value. For instance, there are many contemporary comments on the election of J. F. Rutherford and the expulsion of dissenting directors. That many writers say the same thing does not mean that each is of the same quality. Some simply repeat what they heard or read. None of this is evidence at all. It is gossip. Gossip might be noted by a historian, but it is not evidence. An ethical historian will prune the evidence down to first hand observations. Of these, those that have a point of view become suspect. Why did they say what they said? is an important question. In a controversy, you will find differing points of view. A historian must balance what is said against motive.
Contemporary newspapers are first hand material, but they’re subject to point of view and motive. Nineteenth century papers are notoriously full of lies and fakery. Never take a newspaper article at face value. Ask if it rationally represents events as other testimony represents it.
Original letters and diaries are excellent evidence. But does the content defend someone? Why? Is the defense rational? Does it support other evidence?
Best evidence, aside from being contemporary, has verifiable detail. Suspect documents that lack detail.
Secondary evidence is only important because it gives an overview of current views of the subject. It is not an important contribution to the historic narrative. If one relies on it, he is probably gravely misled.
In this subject area books by Gruss and others become irrelevant. They are secondary, even tertiary sources. Citing them usually does not further quality research.
Assess each evidentiary document using these criteria: 1. Is it contemporary? 2. Is it by a participant? What is their point of view? Why do they approach the matter as they do?
I hope this helps some of our email correspondents.