You're numbers aren't correct.
Employed labour force in Community A: 1000
Community A working in Community B: 750
Community B working in Community A: 250
Total interchange: 1000 (100% of Community A employed labour force)
I'm not really sure what's unreasonable about that, and yes, it could be greater than 100%. All it's doing is couching the number of people commuting between two communities in terms of the smaller communities employed labour force. As an example, the old City of Toronto would have a value massively greater than 100% as far more people commute into downtown to work than live there.
Edit to be clear: this isn't some calculation I made up, it's what Statistics Canada uses to determine whether a CA should be merged with an adjacent CMA.
Employed labour force in Community A: 1000
Community A working in Community B: 750
Community B working in Community A: 250
Total interchange: 1000 (100% of Community A employed labour force)
I'm not really sure what's unreasonable about that, and yes, it could be greater than 100%. All it's doing is couching the number of people commuting between two communities in terms of the smaller communities employed labour force. As an example, the old City of Toronto would have a value massively greater than 100% as far more people commute into downtown to work than live there.
Edit to be clear: this isn't some calculation I made up, it's what Statistics Canada uses to determine whether a CA should be merged with an adjacent CMA.