[S]elf-reporting data can be very misleading.  For instance, in an Australian hospital, 73 percent of staff doctors claimed that they soaped up before interacting with patients.  But a study based on observed behavior showed that only 9 percent of them did. Stephen Dubner, Freaky Thinkers Finish First, Reader’s Digest July 2014.

Add to this insight the notion that many people are also just sure that they know how things work. Together then we realize that getting hard data that supports our decision making is both hard and critical. I’ve seen many successful organizations go for years on your classic seat-of-the-pants management with no real hard reliable data that matched any reality. However I saw this as more a tribute to human ingenuity and hard work than it was smart management.

See How To Get The Project Management Data We Need

So when someone tells us “this is how it is” and that information is critical to our project’s success, I go dig — hard — for data that corroborates that information. I was always surprised at how inaccurate experienced people were.  Inevitably, however, by taking the time to dig for data and to understand the real situation we almost always then found real insight that led us to sustained success.

More examples see To Be Masters Of Our Universe We Need To Dive Deep and How One CEO Came To A Deep Understanding Of His Company

What are you doing to ensure your project is based on data that reflects reality?