Data that is inaccurate, incomplete, inconsistent or out of date can seriously impact business intelligence efforts.
Very early in the development of IT, we discovered that wise old dictum of garbage in, garbage out. GIGO, the catchy acronym for this dictum, reinforced the point that in this discipline, as well as most others, the ingredients and raw materials are essential if you want a good end product. Just as you cannot make a good apple pie with rotten apples, you cannot produce useful reports with bad data.
GIGO is particularly important in the context of business intelligence (BI) because, by definition, business intelligence is supposed to provide us with insights into our business needs from the bits and bytes we have collected.