These days it’s not unusual for someone on the way to work to receive a text message from her employer saying she’s not needed right then.Although she’s already found someone to pick up her kid from school and arranged for childcare, the work is no longer available and she won’t be paid for it.Just-in-time scheduling like this is the latest new thing, designed to make retail outlets, restaurants, hotels, and other customer-driven businesses more nimble and keep costs to a minimum.Software can now predict up-to-the-minute staffing needs on the basis of information such as traffic patterns, weather, and sales merely hours or possibly minutes before.This way, employers don’t need to pay anyone to be at work unless they’re really needed.