I found this very interesting question in ITToolBox yesterday and thought would 'type in' (I would have scribbled or jotted few years back!!) my opinion on this. Let me restate the exact question as it appeared in the forum:
"We are trying to do an analysis of using Absence Manager without Time and Labor. We already have a customized module that feeds online timecards to payroll in peoplesoft. First, is this possible? If so, what functionality would we be missing out on? Everything I have read talks about them together. Is AM just the workflow piece?"
Though the user did not mention their actual requirement, the obvious answer is yes - traditionally over the years T&L has been implemented as a different module from Absence Management. May be the understanding of what these two modules do might help the user take an informed choice.
Absence Management is a module that is specifically designed to manage leaves - that's all it does. It is a very elegant and powerful module that can handle all types of leave accruals, carry forwards, prorations, workflows for approvals etc. It is interesting to note that before AM gained the popularity that it enjoys today, organisations have used Benefits, Monitor Absence in Workforce Admin and even T&L to manage leaves. Absence Management is an independent module and can be implemented standalone with core HRMS.
Time and Labor on the other hand is a much more diverse module that can handle time reporting of employee, track compensatory time offs, enable task based time reporting, calculate overtime and shift premiums etc. If there are no complex rules, T&L can also double up as the module handling leaves of your organisation.
The interdependence of the two modules has to be a thing of version 9.0. With version 9.0, T&L and AM have been coupled very tightly, where entire absence self service has almost been integrated in the timesheet. This could be the reason why it looks as if they cannot be implemented separately.
But the fact remains that both of them are independent modules and the choice of which module to use should completely depend on the depth and nature of your organisation's requirement.