Other people. The case cannot be finalised until reports have written their descriptions, human resources has confirmed the payroll picture, and the organisational chart reflects any recent change. Each of those sits with someone whose main job is something else entirely.
Chase the descriptions early
Send the request for position descriptions at the very start rather than after the duty statement is drafted, because it is reliably the slowest item. Where a restructure or hiring round is under way, decide whether to document the current state or wait for the new one, since a chart that changes mid-preparation forces rework. Set a milestone for the completed team pack before agreeing travel or a start date.
Send the request for position descriptions on the first day, because it is reliably the slowest item and it sits with people whose main job is something else entirely. Everything after it waits: the duty statement, the legal review, and any filing plan. Where a restructure or a hiring round is under way, decide deliberately whether to document the current state or wait for the new one, since a chart that changes mid-preparation forces rework nobody budgeted for.
Set a milestone for the completed team pack and refuse to discuss travel or a start date before it is met. Chase the descriptions weekly rather than waiting to be told they are late.