iSixSigma

5 Whys

Definition of 5 Whys:

The 5 Whys typically refers to the practice of asking, five times, why the failure has occurred in order to get to the root cause/causes of the problem. There can be more than one cause to a problem as well. In an organizational context, generally root cause analysis is carried out by a team of persons related to the problem. No special technique is required.

An example is in order:

You are on your way home from work and your car stops:

  • Why did your car stop? Because it ran out of gas.
  • Why did it run out of gas? Because I didn’t buy any gas on my way to work.
  • Why didn’t you buy any gas this morning? Because I didn’t have any money.
  • Why didn’t you have any money? Because I lost it all last night in a poker game.