ERP implementation
You plan an ERP implementation from the choice of system through to the aftercare after go-live. This page is about the decisions you take yourself, and the questions you ask about them.
Which phases it has
Who decides what
Which decisions you settle in advance
What is an ERP implementation?
On this page, by an ERP implementation we mean the project in which a chosen system is configured around your processes, connected to your other software, filled with your data and put into use by your people. Count the aftercare after go-live as part of it.
In the selection you choose what you buy. In the implementation, decide what you do with it, and budget for the effort of your own people as well, not only for the work of the partner.
Ask three questions at the start: who decides on the processes, who owns the data, and who judges progress without taking part in the build? Record the answers, with names, in the project plan.
Do not treat an implementation as an IT project with a business edge to it.
See it as a series of business decisions that are recorded in software. Which process changes, which exception is dropped, who gets to see the new figures: answer those questions yourself, and do not leave them to your vendor.
Which phases does an ERP implementation have?
On this page we divide an implementation into five phases. Ask your partner which phases and names their schedule uses, and compare them with this division. Each phase shows what you arrange and what you check before you move on.
Per phase: what you arrange and what you check
| Phase | What you arrange in this phase | Your checkpoint |
|---|---|---|
| Preparation | Settle scope, schedule and staffing, and have the steering group start its work. | Is the staffing set out by name, with the time available per person? Or only by role? |
| Design | Compare your processes with the system standard and decide what to adapt and what to have custom-built. | Has every exception been questioned and approved by the process owner before anything is built? |
| Build and configuration | Have the system configured, the integrations built and the data prepared for migration. | Is data cleansing on the schedule, with an owner on your side? |
| Testing | Have key users run their own work through the new system, including the period-end close. | Is testing done with your own orders and exceptions, or only against the specification? |
| Go-live and aftercare | Put the new system into use and agree how open issues after go-live are picked up. | Is it settled who handles aftercare and who answers the questions from your people when the partner scales down? |
If you roll out by site or by division, agree how the phases are planned for each division. For each division, record who approves the design before anything is built, and who approves the test before you go live. You will find each step worked out in the step-by-step plan from kickoff to go-live, and the choice of approach in waterfall or agile.
Who decides what?
Put the split of responsibility on paper before you sign. Below is one possible division into five roles, each with the decision you can assign to it and the question you ask. Adapt the division to your organisation and record it.
Roles and decisions
| Role | Decision you can assign to this role | Check question |
|---|---|---|
| Executive sponsor | The goal, the budget, and whether the project continues when it hits setbacks. | Does the executive sponsor take part in the decisions on scope, or only sit on the steering group? |
| Your own project lead | Progress, escalation and the daily trade-off between time, scope and quality. | Has room been cleared in the diary, or does the role come on top of a full job? |
| Process owner | Which process changes and which exception is dropped. | Has one person been named for each process who is allowed to say no to an exception? |
| Key user | Whether what was built matches the way the work is done in practice. | Is the key user involved in the design, and not only in testing? |
| Implementation partner | The configuration, on the basis of what you decide. | Does the quote state which decisions are yours, and who judges whether something is extra work? |
Also read how to assess an implementation partner before you sign.
Which decisions do you settle in advance?
Four moments at which we advise you to record a decision deliberately, each with the question you ask out loud. At each moment, ask your partner what reversing the decision would affect.
When defining the scope, before work starts
Record what is and is not in this project, and which site or division falls outside it.
What would it mean for this project if a division that is now outside it joins after all?
At every departure from the standard
For every exception you have had built, ask who maintains it and what that maintenance costs when the system is updated.
What does it cost us to change this process to fit the system rather than the other way round?
At the data migration
Decide which history moves across and in what form. Record who cleans up the data.
Who owns this data, and who says whether it is good enough?
At the decision to go live
If you decide to go live with known open issues, record for each issue who resolves it and how you check that it has been resolved.
Which open issues do we accept, and who resolves them?
Which checkpoints do you discuss at the start?
Five checkpoints, each with a tip. Discuss them at the start with your project lead and your partner.
Check whether the staffing is set out by name
If the plan only shows a role, ask who does the work. Name the person assigned to each role, and the time that person has available.
Have the names included in the contract.
Ask for the reason behind every exception
Ask every department that wants an exception for the reason. Let the process owner decide whether that reason carries enough weight to build for it.
If nobody can explain an exception, ask whether it is still needed.
Ask who checks the data quality
Assign data cleansing to your own organisation, with an owner for each type of data, and put it on the schedule.
Have the owner of each type of data record the requirements that good data must meet.
Test with your own work, not only against the specification
Test not only against the specification, but also with your own orders and your own period-end close.
Also test with a busy period from your own records, not only with a clean example.
Ask who judges progress
Ask who reports on progress, and whether that party is also building. If so, agree who else reviews it.
Also have progress judged by someone who is not building.
If your project is stuck, see stalled ERP implementation.
Going deeper per topic
Take two decisions before the implementation: the choice of partner and the choice of system. Each has a page of its own.
Frequently asked questions
- What is an ERP implementation?
On this page, we use the term for the project from signing the contract to the point where your people use the system in their daily work: configuring, connecting, moving data across and learning to work with it.
Plan it from the choice of system through to the aftercare after go-live, and agree who picks up open issues from daily use.
- How do you get a clear view of the scope of an ERP implementation?
Ask your partner which factors they include in their estimate. Ask, for example, how they weigh the number of sites, what falls outside the standard, the number of integrations and the state of your data.
Also ask for a schedule per phase with names attached, and have it reviewed by someone who is not taking part in the build.
- What is the difference between ERP selection and ERP implementation?
On this page we use this distinction. In a selection you choose what you buy. In an implementation you decide what you do with it, such as which process changes, which exception is dropped and who decides what.
Give the implementation the same attention as the ERP selection, including when it comes to the effort of your own people.
- Who is responsible for an ERP implementation?
Record that before you sign. We advise this split: the client is responsible for the goal, the budget and the decisions about processes, and the partner for the configuration that follows from those decisions.
Check whether that line is in the quote, and say it out loud before you sign.
- Which checkpoints do you discuss at the start of an ERP implementation?
On this page we name five checkpoints. Check whether the staffing is set out by name, ask for the reason behind every exception, ask who checks the data quality, test with your own work and not only against the specification, and ask who judges progress.
Discuss them at the start with your project lead and your partner, and also have progress judged by someone who is not building.
Further reading
This page covers the phases, the roles and the decision points. The articles below go deeper into carrying it out.
- Step-by-step plan from kickoff to go-live
- Outsource it or do it in house?
- Preparing your data for migration
- Bringing your people along before go-live
- Ready to go live, or not yet
- Why the party that builds should not also judge progress
- Waterfall or agile
- Choosing the right implementation partner
- Extra work: who judges what falls outside the scope
This page was last reviewed on 11 October 2026.
Have an implementation watched over
In every project, ask who judges progress, and whether that party is also building. If you would like to discuss that for your own implementation, get in touch with us.
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