Eligibility is a filter over records
- Does the person hold the skills the service type requires?
- Are the required credentials currently in date?
- Are they available — not on leave, not already committed, within hours?
- Do they cover the territory the work sits in?
Assignment is a decision with a name on it
Once the eligible set exists, someone chooses. That choice carries information the filter cannot hold: who this customer has met before, who is being developed on this work type, who is closest to finishing their morning job, who you would rather not send back to that address.
Assignment records the outcome — person, role on the crew, date, time window — and, crucially, who decided. When a job goes wrong, 'who assigned this crew' is the first question and the hardest one to answer from memory.
Why conflating them is expensive
Businesses that assign straight from memory are running the filter in someone's head. It works while the head belongs to one person who knows everybody. It fails the week that person is on holiday, or the month you cross into two crews' worth of complexity.
The failure is not dramatic. It is a technician sent without the credential the site required, a second visit, an apology, and an afternoon of margin gone — a cost that never gets attributed to the scheduling process that produced it.
Where dispatch sits
Dispatch is neither of these. Scheduling and assignment plan the work; dispatch executes the day as it actually unfolds — reacting to the running-late job, the callback, the truck that will not start. Assignment is the input dispatch works from.