Interestingly, I inherited a process where the previous person stored integer values in a varchar(3) field and did poor quality checks on the data coming in. The people doing data entry often misread a zero for the letter D.

I was tasked with trying to code for some statistical samplings. The problem was, I could not match the previous statistics. Most years were very close and could mostly be attributed to different rounding methods between SQL Server and the stats package they had been using. One year of data was way off. This is when I found that I had two entries in the integer holding Varchar(2) field that were entered as D0. I had used logic to make the D a zero. However, the old stats package had apparently been treating it as hex and converted it to 208.

It was near impossible to convince the data owners that their data quality was responsible and that their previous reports were in error.

So, I guess my point is that, aside from poor QA on the data entry, that we do not always know how other tools will handle data when we do poor data typing.

By the way, it took 2 other analysts and a statistician to convince the data owners their data was of poor quality.