bingo
What part in particular is taking longer than expected?
As someone who has worked on projects like this (and is in fact working on a project very much like this right now), I can totally sympathize with delays. I would totally understand something like "we're delaying it to reprocess data that had issues the first time". That would not only not be embarrassing, but would me confident that someone cares about the quality of their data.
If the delay was just a week or two, I understand not giving a reason if you're going into crunch time and trying to finish the last bits as quickly as possible without embarrassment. But if you're delaying by months, you should give a reason or reasons as for why. Again it's nothing to be ashamed of.
