Where to Start Reading

Fifty notes is more than anyone needs at once. These are the paths that fit the common situations.

Figures do not reconcile and nobody knows why

One person, four records, for identity.

Departments, sites and cost centres.

Reconciling between systems, for the four comparisons.

Investigating a wrong figure, for the sequence.

Start here regardless of which module is being blamed.

A purchase has been proposed

The question to ask first.

A suite or several products, framed around ownership.

Evaluating against the joins.

Reading a vendor claim.

What the joins actually cost, which is the number the business case needs.

A project is underway and struggling

Which join to build first, which is usually the answer.

Moving off an old system.

Four systems, four clocks.

How these estates fail.

The estate works and costs too much to keep working

The spreadsheets in between.

Who owns the whole thing.

When one module upgrades.

What the joins actually cost.

If you read only three

What sits between the modules, because the framing is the whole subject.

Which system owns which rule, because the register prevents the classic defect.

Reconciling between systems, because it is the only control that detects a silent failure.

A closing note

Nothing here is legal advice, and the notes say so where it matters. Obligations around working time, pay records and personal data vary substantially by jurisdiction.

No vendor material and no product names. Every number worth having in this subject is one you produce from your own systems, and the notes say how to produce each.

And this collection deliberately does not cover how to build a rota, record attendance, manage absence or run payroll. Those are subjects in their own right; this is about what happens between them.

If you have one hour

The shortest useful route.

Run the headcount comparison across your systems.

Compare hours sent against hours paid for one period.

Two queries.

They will tell you whether the chain reconciles, which join is worst, and whether the rest of this collection is urgent — which is more than most organisations discussing this subject have established.

Reproduce the workflow

For another way to make this requirement testable, consult browse the integration catalogue. Reproduce the case with real roles, codes, failures and recovery steps.