When we look closely at cause and effect, we see that a "cause" and an "effect" are the same thing, or stated another way, a single thing may be both a cause and an effect. They differ only by how we perceive them in time.
When we start with an effect and ask why it occurred, we find a cause; but if we ask why again, what was just now a cause becomes an effect. An example of this is shown in the table below listing a column of effects and a column of causes (read left to right, top to bottom).
Notice how the cause of one thing becomes the effect when you ask why again. The cause of the "Injury" was a "Fall", and when you ask why "Fall", it changes to an effect and the cause is "Slipped." This relationship continues as long as we continue to ask why.
Knowing this principle helps us understand why people can look at the same situation and see different things. One person might see an effect while another sees a cause. In this example, if you are the person who fell, you might see slipping as the reason for your fall and just try to be more careful next time, while the safety engineer might see the wet surface as the cause of your fall and take steps to wipe up the spill. Someone else might see the lack of maintenance as the root cause of the fall.
To be effective problem-solvers, we must understand all the causal relationships independent of these biased perspectives, and this is best done by documenting each stakeholder's perspective of the cause and effect relationships.