==Decay vs. Cut-offs==
One major distinction in measuring accessibility is how parameters are set for determining whether a destination is accessible. One method is to create a time cut-off. For example, one can ask
, how many jobs can be reached in 30 minutes using transit from a given location? Or, how many household/job combinations are there within 30 minutes of each other along a transit line or in a transit system? The alternative is to use a decay function. A decay function weights destinations based on how far they are, so that farther locations are given less weight than closer ones.