Why the number of sessions is different when I change a funnel step from required to optional?

When you use a funnel report, you can mark steps as required or optional. If visitors skip the optional steps, they stay in the funnel and aren’t counted as drop-offs. On the flip side, those who skip required steps get tagged as drop-offs.

However, understanding the session count in funnel steps can be tricky. Sometimes it seems off, but fear not – the session number is accurate. These examples should help clarify things.

Example 1

Comment:

In the second funnel definition, the algorithm matched the visitor’s path in the following way:

1. Found A at timestamp 01 (first A is taken)
2. Found B at timestamp 02 (first B is taken, ignoring A because it’s optional)
3. Found C at timestamp 03 (first C, after B, is taken)

• Found sequence: B, A, C
• Funnel definition: A, B, C
• Result: B, C

Example 2

Comment:
In the second funnel definition, the algorithm matched the visitor’s path in the following way:

1. Found A at timestamp 02 (A is taken)
2. Found B at timestamp 00 and 03 (last B is taken because it’s after A)
3. Found C at timestamp 01 and 04 (last C is taken because it’s after B)
4. Found D at timestamp 05 (D is taken)

• Found sequence: A, B, C, D
• Funnel definition: A, B, C, D
• Result: A, B, C, D

Example 3

Comment:
In the second funnel definition, the algorithm matched the visitor’s path in the following way:

1. Found A at timestamp 02 (A is taken)
2. Found B at timestamp 00 and 04 (last B is taken because its timestamp 04 is after A at timestamp 02)
3. Found C at timestamp 01, 03 and 05 (middle C is taken because its timestamp 03 is after A at timestamp 02)
4. Found D at timestamp 06 (D is taken)

• Found sequence: A, C, B, D
• Funnel definition: A, B, C, D
• Result: A, B, D