Variable scaling for index

[Adrienne Wold]

Hello, I am trying to create an index using two variables, one is a binary indicator and the other is a 5-point likelihood scale. What is the best way to standardized the latter to be consistent with the former?

[Nick Cox]

Naturally (whatever - 1) / 4 maps [1, 5] to [0,1]. I don't know what other solutions you had in mind.