# Kinds of Cause and Effect (AND, OR)

The relationship between cause and effect written by "### because +++."

If there are more than two causes, writing becomes complex. The ideas, "AND condition" and "OR condition", makes that simply.

There are Relation Diagram , Why-why Analysis and so on as to write the relationship. But these methods does not care about "AND and OR". "AND" is more difficult to use.

## AND condition

The example of AND condition is that "I do not have umbrella because the weather forecast is fine and the weather of yesterday was fine."

Both condition is needed.

## OR condition

The example of OR condition is that "I have umbrella because weather forecast is rainy or cloudy".

At least, one of these condition isneeded.

## Methods Using the Difference of AND and OR

Some methods cares about the difference.

FTA of Reliability Engineering cares to calculate probability of phenomena.

In Decision Tree , OR relationship is expressed as nodes from same node. AND relationship is expressed the depth of nodes.

We can analyze AND and OR by Associations Analysis . But we need to care about the consideration of output of this method. ( Relationship Between If-Then and Cause-Effect )