Implementing a new WSSI or MFP system: How to do it right

The WSSI (Weekly Stock Sales and Intake) is the engine that powers the decision making of Buying, Planning and Trading teams. Installing a new engine – while keeping the business running – might seem a daunting task, but, done right, it could transform your business. 

You may not have a WSSI system to speak of, having preferred to use Excel tools with which everyone is familiar. You may have a WSSI or MFP (Merchandise Financial Planning) system that is failing both you and your business. Or you may have a system that has served you well for many years but is not futureproof and will soon cease to be fit for purpose – if indeed it is even supported. 

Either way, you recognise that the time has come to implement a new WSSI or MFP system.

What do you need to consider to ensure that the new system delivers the benefits you have been promised, your project avoids painful and costly delays, and that the change is welcomed by your people?

At First Friday we have supported a large number of WSSI and MFP projects over the years and I’ve worked on quite a few of them myself, and I thought it about time I shared my thoughts on some of the most important areas you need to consider to help make your next project a success: 

  1. Define your merchandise planning and WSSI processes
  2. Define your MFP and WSSI system requirements
  3. Defining your MFP and WSSI reporting needs
  4. MFP / WSSI software selection
  5. Appointing suitable subject matter experts
  6. Managing change
  7. New WSSI / MFP system training
  8. Sustaining engagement

Define your merchandise planning and WSSI processes 

Your WSSI or MFP system is a tool to support a process; it is not the process itself.  So before you start building the system, you first need to think about how you will want to work. 

Start by reviewing your current process and identifying opportunities for improvement:

  • Is there an established process, or have all areas developed their own ways of working?
  • Where are the pinch points in the current process?
  • Is the current process documented? We are often told this isn’t needed because the current process is broken. But an understanding of the “as-is” will be required for effective change management and training, which must focus on helping people understand what will be different about how they will work.

With an understanding of the current process, you can then move on to think about the future and clarify your strategic intent:

  • Do you want merchandise planners to work bottom-up and managers to review the roll-up?
  • Would it be useful if managers could take a top-down view?
  •  How would you want to reconcile the top-down and the bottom-up views?
  • How should different channels (Retail/Ecommerce/Wholesale) play into the process?
  • Are there new metrics you would like to use to manage performance?

 Finally, pull back and establish what is feasible in your business:

  • Can you access all the data you will need?
  • Does your organisational structure support what you are going to ask your teams to take on? (I’ve seen teams bristle when the additional complexity they agree they need has been introduced into their role with no additional support)
  • Are you prepared to build/fund organisational change to support the desired process?   
  • Will you need to adopt a more pragmatic approach to avoid overcomplicating the solution? A pragmatic approach can be important. You may get seduced by the available features within the software. Always relate back to your objectives and be aware of the difficulty and associated costs of adopting some of those features.

Define your MFP and WSSI system requirements

Prioritise your requirements before you start looking at potential solutions.  The possibilities are endless, and it will feel a bit like being in the proverbial sweetshop! 

If you have defined your process, and are aware of your data limitations, you will be better equipped to define what you really need, as distinct from what it would be nice to have.

  • With the role of Retail/Ecommerce/Wholesale in the process defined, you will be able to specify the levels at which they should be included in the WSSI
  • Do you need to operate in more than one currency?
  • Do you want to work in Cost/Retail/Blended/Units?
  • Have you identified new metrics you want to include?
  • What degree of reconciliation between bottom-up and top-down views do you require?
  • Do you want a formal systemised approval process?
  • Will you want WSSI / MFP to integrate with other systems (e.g. Assortment Planning?)

Define your MFP and WSSI reporting needs

Don’t forget your reporting requirements! In almost every project I’ve worked on, reporting has either been forgotten or has caused issues.

I’ve also seen projects where complexity is introduced into the WSSI to satisfy performance reporting requirements.  These variables then have to be forecast. 

Remember: Your WSSI/MFP system is a planning tool – not a reporting tool. 

The WSSI may have been used for performance reporting in the past, and a cottage industry of data exports built alongside it:

  • Do you use a WSSI report in meetings? Is this still required, and how will it be delivered?
  • Can you deliver data from the WSSI / elsewhere to replace existing reports/activity?
  • How much of what people say they want to have in a WSSI could be delivered from reporting, and how much is genuinely required as forecast?

MFP / WSSI software selection

Once you have clarified your requirements, you are ready to undertake your selection of the software itself.  

  • Don’t be put off by thinking this needs to be a huge system; a simpler solution may be more cost-effective and equally beneficial.  An off-the-shelf “vanilla” solution may sound attractive, but I’ve yet to see a truly vanilla implementation. In our experience, some modification is always required (almost always at additional cost).
  • Consider the flexibility of the proposed solution, and be realistic about the availability/quality of data in your business.
  • It’s also critically important that you include representatives from both the relevant business functions and IT in the selection. 
  • While the business users will understand their requirements, the most complex piece of the WSSI/MFP implementation will be the integration with your other systems, and it is so often data issues that cause delays.
  • Finally, don’t be afraid to seek help with your review process; it can be difficult to appreciate the differences between, and potential of, new systems – especially if you are implementing a WSSI system for the first time.

Appoint your subject matter experts

Your system integrator will need access to subject matter experts (SMEs) to inform the design and build of the system to your requirements. 

Think carefully about who you will appoint:

  • Do they have enough credibility within the business for their decisions to be respected? (SMEs will be challenged by peers, nervous about change)
  • Do they have enough experience of both your own and other businesses to future proof your solution, or have they only known your way of working? (I’ve seen new systems built to replicate the old way of working, simply because that was all the SMEs had ever known)
  • Will they be open to new ideas offered by the Systems Integrator, but also be able to distinguish between the “must-haves” and the “nice-to-haves”?

I’ve seen all-singing-all-dancing solutions way too complex for the business to handle. Sometimes caused by the inexperience of the subject matter experts.

Once you’ve answered these questions, you should now be in a position where you understand your requirements and who needs to be involved in the project. So now it’s time to start thinking about how you’re going to manage the actual implementation…

Change management, change management, change management

There are many reasons why projects fail, and they are not all about the system itself or the data. 

You will need to invest in managing the change into the business if your people are to embrace it. So often this vital element is forgotten – or squeezed at best. 

In the worst cases, this results in people not using the new system – and I’ve seen many cases of the new system being used to mimic old ways of working, with teams paying only lip service to the planned change. 

  • How different is the desired way of working from the way you work now? How will you communicate it and when will you start? Start drip-feeding information to avoid storytelling by the water cooler
  • How will you secure buy-in from the interested parties and ensure that they do not try to use the system to replicate the current ways of working? Your managers are key in this, even if they are not going to use the system themselves; they need to be reassured that everything they need will still be available, and to know what else will be available to them if they ask for it. They will also need to allow their teams time to adjust to new ways of working and to support them through that change.
  • Have you worked out who is going to manage this change for you? 

Training needs

Your system implementation represents a considerable investment, but your people need you to invest in their training if they are to use the system to work in the way you intend.

Don’t leave the planning of your training until the last minute; establish who needs training in what and identify upfront the scale of training and likely resource required – trainers and rooms – to deliver in an appropriate time frame.

  • Have you planned – and budgeted – for training that includes the skills required to make decisions with the system, as well as the ability to push the buttons? Training must go much further than navigation around the system and what buttons to press.
  • Have you ensured that training is role-based so that those impacted by the system are included as well as hands-on users?
  • How will you train them on both the system and the WSSI / MFP ways of working?
  • Do your trainers have the right business experience to train a complex subject? Will they be respected by the delegates and foresee the kinds of question that might be asked?

These are all important questions that you need to consider – and answer – before you move on to the final stage…


When the project team has disbanded and the third parties departed, how will you sustain enthusiasm for the new system and ensure that best practice is maintained? 

Consider appointing super users, responsible for running workshops to share knowledge with their peers. 

Also, have a plan in place for training new starters and internal promotees to the required standard, and whether this will fall within the capabilities of your business-as-usual training team.

By the time you get to the implementation stage, you’ll likely have made a sizable investment. Ensuring your teams are able to effectively use the new tools and follow any new processes is critical to ensuring that it’s not been a waste of time and money – and that it does deliver on the aims that you identified at the very start of the project.


Need help with a new MFP/WSSI implementation?

Our experts can help you work out the best processes, find the right system, implement it, and train your staff how to use it.  Learn more about our System Transformation services or get in touch.

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Kathryn Fletcher

About the author: Kathryn Fletcher

An experienced retail professional, Kathryn provides additional specialist consultancy on client projects as part of First Friday's extended Retail Consulting Team.

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