MES Buyer Checklist: 25 Points to Check Before You Sign

Key takeaways

• Check how the MES captures stops before you look at dashboards.
• Ask to see the OEE math on your own numbers. If it does not match a hand check, walk away.
• Operators decide if the data is good, so test the screen they will use.
• Integration was the top MES buying need in one industry survey (44%), security and compliance second (43%).
• Get the pilot scope, baseline and decision date in writing.

The short answer: a good MES buyer checklist starts on the shop floor, not in the brochure. Check how stops get logged, whether the OEE math holds up, and whether operators will use it, before features and price.

This checklist is for plant managers, CI leads and engineers who are shortlisting an MES or light MES. Fabrico, a computer vision enabled Manufacturing Performance Platform, is one of the systems you can score with it. Print it and take it into every vendor meeting.

Why use a checklist at all?

MES demos look alike. Every vendor shows a green and red dashboard. The differences are in how the data gets there and who keeps it clean. A checklist makes every vendor answer the same questions, so you compare like with like.

Remember who you are really competing with: 54.4% of small and medium manufacturers still run on pen and paper or spreadsheets. The MES has to beat the clipboard on speed and trust, or the crew will go back to it.

1. Data capture: how do stops get in?

• Can it connect machines without a PLC? (Fabrico connects through a PLC, an IoT device or an AI camera.)
• Are stops logged automatically, with start and end time?
• Does it split own stops from starved and blocked time?
• Does it catch short stops under your micro stop cutoff? Our guide to automatic downtime tracking shows what good looks like.
• How does the operator add the reason, and how many taps does it take?

2. OEE math: can you trust the number?

• Does OEE equal good count x ideal cycle time / planned production time?
• Can you set the rated speed per product, not one per machine?
• Can you see what counts as planned time, and who can change it?
• Can it show Availability, Performance and Quality, not just one OEE figure?
• Will the vendor run one of your shifts through it and match a hand check?

Watch for the three classic fudges: breakdowns booked as planned stops, a good day's speed used as the ideal, and scrap counted as good.

3. Operator use: will the floor use it?

• Is the line screen readable from where the operator stands?
• Can a new operator use it after one short walk through?
• Does it measure the process, not the person? This matters for works councils and the EU AI Act.
• If cameras are used, what is kept, for how long, and who can see it?
• Does the supervisor get a shift view without building reports?

4. Integration and security

• Where does it sit in ISA-95? MES is Level 3; it should not try to be your ERP.
• What does it read from ERP, and what does it send back?
• Is the vendor's development judged against IEC 62443 4-1 and 4-2?
• Who owns the data, and can you export it?
• What happens to data collection if the internet link drops?

For the IT side, see our cloud MES buyer's guide for IT questions.

5. Rollout and commercial terms

• Is the pilot scope one line, with a baseline and a decision date written down?
• Who does what on your side and on theirs, week by week?
• How is the price set: per plant, per line, per user?
• What does it cost to add the next line, and the next plant?
• Which named customer results can they show, with the customer's name on them?

How do you score vendors with the checklist?

Give each point 0, 1 or 2, and weight the sections. A sample scoring sheet:

Sample scores (illustrative, not real vendors). Vendor B has the nicer screen, but Vendor A wins because its data capture and OEE math hold up. Weight the sections to your plant; these weights favour data you can trust.

Who should fill in the checklist?

Not one person. Split the sections so each part is scored by the people who live with it:

• Supervisor and an operator: data capture and operator use.
• CI or OEE lead: OEE math.
• IT: integration and security.
• Plant manager and finance: rollout and terms.

Score each vendor right after its demo, while the answers are fresh. Then compare the sheets side by side in one meeting.

Red flags during the buying process

• No answer on how starved and blocked time are handled.
• An OEE figure that will not match your own hand check.
• A pilot with no end date or no success measure.
• Customer results with no customer name.
• A claim to be the "Gartner MES Leader" for 2025. Gartner's 2025 MES research is a Market Guide, and a Market Guide ranks nobody.

For more questions to ask, see our MES selection guide.

Where Fabrico fits

Fabrico is a computer vision enabled Manufacturing Performance Platform. OEE and light MES come first: automatic downtime logging that keeps own stops, starved and blocked time apart, and OEE live by line and shift.

• Machines connect through a PLC, a Fabrico IoT device or an AI camera; the machine itself needs no PLC.
• The operator confirms the reason in one tap, with a camera clip as evidence where a camera watches the line.
• Losses priced in money and ranked.
• A work order with its cost to the right technician when a stop is a breakdown.

Named results: ABB, 20% less downtime; Ficosota, OEE from 53.1% to 59.6% and good output up 23.2% a month. You start on one line, with a baseline and a decision date agreed in advance. There is no free plan and there are no tiers: each plant gets a quote. See light MES.

Frequently asked questions

What should be on an MES buyer checklist?

Data capture, OEE math, operator use, integration and security, and rollout and commercial terms. Start with how stops get logged.

How many vendors should we shortlist?

Two or three is enough to compare. More than that and the demos blur together.

Should IT or operations own the checklist?

Operations owns it, IT signs off on the integration and security section.

How do we test the OEE math?

Give the vendor one real shift of counts and stops, and check their OEE against your hand calculation.

Is a light MES enough?

If your main pain is downtime and line performance, a light MES focused on OEE often covers it. Check it against the same list.

Score Fabrico in a demo

Bring this checklist. We will go through it point by point on a real line setup.

Request a demo · Contact us