Has OPEC misled us about the size of its oil reserves? Does it matter?
The key words are "OPEC Secretariat" which refers to the OPEC staff located in an office in Vienna. That office is where BP presumably gets its information about OPEC reserves. The EIA lists the OPEC Annual Statistical Bulletin put out by--you guessed it--the OPEC Secretariat. Alas, the Annual Statistical Bulletin tells us under the heading "Questions on data" that "[a]lthough comments are welcome, OPEC regrets that it is unable to answer all enquiries concerning the data in the ASB." In other words, trust us. So, information about OPEC reserves comes either from the OPEC offices in Vienna or from member countries. Some analysts may adjust those figures based on the few shreds of evidence that are available outside of official government pronouncements. But, in reality, there are almost no hard facts when it comes to OPEC reserves.