On 2011-05-22 11:07, Ian Goddard wrote: > Peter J. Seymour wrote: >> >> In my experience merging should be regarded as a one-way process, if >> you do it, you need to be confident you will not want to revert. > > Coming from a scientific background I have real problems with this view. > Any conclusion is simply the holder's best summary of available data at > the time. It is open to being falsified by better data becoming > available and hence the required confidence you mention must be lacking. > I suppose it depends on the extent to which a can of worms is being created. A difficulty with geneological data is that merged data may be built on by new data and so an improper merge may end up contaminating more than just the records immediately involved. There may be no clean way of backing out. On the other hand, if caught early it may be possible to backout tidily. Peter