This is an important point. Before being confronted with this situation, I assumed that everyone would simple retract their papers if they found out they made a mistake. Now I know that it is not that simple. If you find a discrepancy you need resources and willing staff to repeat experiments. It took much longer than I had expected. Because the Xa21 project is central to my lab, there was no question that we would work to correcting the record. However, I do understand that some scientists may not have the staff in place to do the work. In addition, if results are questioned from a project that the PI worked on many years ago, they may no longer have materials or expertise to address the issue thoroughly. In that case, they may leave it to other labs to sort out.