Separate the method from the app
A course on a task manager teaches an application. A course on planning, prioritising and finishing teaches a habit that outlives whichever application you use next. Tool courses are quicker to finish and easier to abandon, because a new tool without a method usually becomes a tidier version of the same backlog.
Ask what the advice rests on
This field mixes genuine research on attention, habit and teams with a great deal of confident personal method. Both can help. What separates them is whether the material says where its claims come from and under what conditions they hold. Be wary of anything presenting a single routine as universally correct.
Decide whether the problem is yours or the organisation
Personal productivity material assumes you control your own time. Project management, delegation and communication courses assume you are coordinating with others and often that you have some authority. Choosing the wrong one is the usual reason a course feels correct and changes nothing.
Be clear about whether you need a credential
Some project management training leads towards a recognised certification, and some simply teaches the practice. These cost very different amounts and take very different time. Where a course is preparation for an exam that is bought separately, the listing says so rather than describing it as the certification itself.
Short is often correct here
Unlike most subjects in this directory, a good productivity course can be an hour long, because the content is a handful of ideas and the work is applying them. Length is a poor proxy for value in this category. What matters more is whether the course asks you to change something while you are taking it.