The damage one historian with erroneous conclusions can do.

Army historian of World War Two and the Korean War, S. L. A. Marshall

Historians can be enormously influential.

Many people tend to think of historians as tweedy characters, looked up in their rooms wearing thick glasses and going through piles of books. That isn't the case of course, although they do read a lot, but they do research and that research tends to get reflected in their published works. That is inevitable.

Historians aren't always correct.  More often than not, when they're not, its simply inadvertent.  Not everyone understands everything they study or see, and errors can be made.  Those errors can become very hard to correct later.  For example, the widely erroneously believed myth that cavalry played hardly any role in World War One has proven to be darned near impossible to correct, in spite of it simply being demonstrably wrong.  It might never be corrected.

But an error that's intentionally created to advance a point is another matter, and that appears to be the case with the legendary findings of S. L. A. Marshall in his still in print book Men Against Fire.

Men Under Fire reported Marshall's conclusions that only 25% of troops fired their weapons in combat during World War Two.  The finding was so influential that the Army adjusted its training and doctrine as a result, applying its newly learned lessons during the Vietnam War. The problem is that Marshall's own data didn't support his conclusions and they were wholly incorrect.

This did great damage to the U.S. Army at the infantry level.  Marshall's work was later drawn into question and discredited.  Marshall himself has received some criticism for his behavior in how he came to bully his research assistants.  But the book is still in print all these years later and it still shows up on Army recommended reading list, showing I suppose how prevalent an influential work can be once its received initial approval.  At the training level, the Army moved on after Marshall and went back training marksmanship, but not before many years of his influence had had an impact.  The Army's historical branch should withdraw the book lest it have any renewed influence, although that risk is no doubt slight. For historians, and the readers of history, the story has a lesson all of its own.