alt Hacker NewsOne thing I noticed on the CS PhD side of the house is because many researchers don't want others to easily build upon their work (for whatever reasons), they don't often release the source code/data required to quickly validate it. This is a recipe for shortcuts, errors, and even in the worst cases, fraud.
When I was in grad school, this was the norm across the board (engineering/physics). No one wanted to reveal their secret sauce.
Things have changed since, but in my time, if a journal required source code for publication, most of the professors in my department would not have published there.