It's not what you don't know that kills you but what you know that isn't so.

— Tom DeMarco The Deadline (1997)

Source and credibility

Wikiquote does not flag this quote as disputed or misattributed.

Source: The Deadline (1997), p. 284.
Work: The Deadline, 1997
Source quality: Precise citation Points to a specific work with a page, chapter, date or similar locator, so you can look it up.

Why Does Software Cost So Much?: And Other Puzzles of the Information Age (1995)

Peopleware: Productive Projects and Teams (1987)

Peopleware: Productive Projects and Teams (1987)

Peopleware: Productive Projects and Teams (1987)

The Deadline (1997)

Peopleware: Productive Projects and Teams (1987)

Quote text and notes from Wikiquote: Tom DeMarco (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.