The NBI has many of the same problems as the IGI.  In fact, some of the data was brought over from the IGI. 1.  Parish names are sometimes incorrect. 2.  Church dedications are incorrect. 3.  Individual names/dates are incorrect. 4.  Some entries were omitted. It has been estimated that the IGI's error rate is about 10%.  I haven't seen statistics for the NBI.  But ANY entry you find should be checked against the parish register or the Bishop's Transcript. But both of these indexes are still a good starting point.  Just don't don't trust them completely. I have also found errors in the dedications noted in White's and Kelley's Directories.  You best bet is to go to the church and lay eyes upon the signs.  A handful of churches were rededicated after a major rebuild or restoration.  Normally, the old dedication was renewed, but it was an opportunity to recast the dedication to one that everyone felt was more appropriate.         Lou