To me it's quite simple:

  * If there's no clear way to get the raw-data 
  * If it's unclear how the data was gathered   
  -> the results are most likely fabricated

One strange psychological effect I've seen is that especially in medicine some people themselves spend a lot of time rigging data to get to their PhD, but in the end they absolutely trust in anything published in the field. "The science nowadays is so good - medical scandals today are completely impossible"