This situation may not have any easy resolution. If you have been involved in the collaboration for a long time, you will likely be reluctant to do anything that would result in your walking away from all the work you put into it. Your personal relationship with the collaborator may create a second barrier. If he is a friend, you may be hesitant to question his integrity. If he is a supervisor, you may be reluctant to jeopardize your job or your career. Your situation may well be worse, however, if you allow your name to be attached to fraudulent work, whether or not you directly perpetrated the fraud. Some action must be taken before any of the work gets disseminated.

If you feel comfortable talking to your collaborator as a colleague, you could try becoming more insistent on seeing the raw data. You could remind him that, since your name will be attached to any publication, you feel partly responsible for understanding how the raw data was reduced to tabular form. If you are dealing with someone in a supervisory role, you might try suggesting that you want to learn how the data analysis was performed. Getting access to the raw data may clear up your concerns, allowing the matter to end there.

It may be the case, however, that suspicions remain after you see the raw data or that you are never given the raw data. While you do not know at this point if the analysis is fraudulent, you need to keep your focus on not allowing fraudulent research to be published. One option would be to talk openly with your collaborator about your concerns to see if he has explanations that satisfy you. If you are not able to do that, you might try blocking dissemination of the results. You may or may not be able to do this depending on how much leverage you have as a collaborator. Blocking dissemination also requires ongoing vigilance on your part, which may not be practical and does not really address the core issue of the possible research misconduct. A final option would be to contact the MPO. The MPO will have more leverage to get to the bottom of the situation and can ensure that you are not held accountable for the misconduct of someone else.