This article is part of a six-phase series on ERP implementation
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By Lee Clarke, Senior Business Director
– Last Updated: May 2026
The most expensive ERP mistakes are made during discovery and planning – not at go-live. Scoping errors, governance gaps, and the wrong vendor choice don’t surface immediately. They compound through every phase that follows. Bringing experienced ERP interim specialists in at this stage is the most effective way to avoid the problems that derail programmes later, when they have become far more costly to fix.
Most ERP programmes that fail don’t fail at go-live. They fail in the weeks and months before a vendor is even selected – during discovery, planning, and scoping – when the decisions that determine everything else are made without the experience needed to make them well.
This is the phase that tends to get compressed. Boards want to see momentum. Internal teams are confident in their knowledge of the business. The system integrator is already in the room with a methodology and a timeline. The pressure to move forward is real, and it arrives before the organisation has properly understood what it’s actually moving toward.
The consequences show up 18 months later: a system that doesn’t reflect how the business operates, a scope that expanded because it was never properly defined, a vendor chosen for the quality of its pitch rather than its fit for the organisation. By that point, the cost of correcting course is significant – in terms of budget, time, and in the credibility of the programme leadership.
Getting this phase right matters more than any other single variable in ERP delivery.
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This is not a criticism of internal capability. Finance directors, operations leaders, and IT teams typically understand their business in great detail. What they rarely have is recent, direct experience of what an ERP programme at this scale actually demands at the outset.
Most organisations go through a major ERP implementation once every ten to fifteen years. The internal team that led the last one has often moved on. The institutional memory of what that programme taught – about vendor selection, about scope discipline, about what to push back on when the implementation partner presents its standard approach – is largely gone.
That gap matters most during discovery and planning, because this is the phase where assumptions harden into commitments. Processes that aren’t examined become requirements that go unchallenged. Workarounds that have persisted for years get built into the new system design. Integrations that are genuinely complex get assessed in a workshop and logged as resolved.
Experienced ERP interim specialists bring something different: multiple implementations, in different organisations, under different pressures. They have seen what the discovery phase misses when it is run without rigour, and they know which questions to ask before those gaps become problems.
The discovery phase has a straightforward objective: to build an accurate picture of how the business currently operates, not how it is documented, but what is actually happening day-to-day.
That distinction matters. Most organisations have documented processes that reflect how things were designed to work. What they also have – though rarely written down – is a layer of informal workarounds, manual interventions, and exception-handling routines that have accumulated over years. These exist because the current systems have limitations, because processes were never properly designed, or simply because the business has changed and the formal procedures have not kept up.
If these aren’t surfaced during discovery, they get carried into the new system. The ERP implementation that was supposed to improve how the business operates ends up replicating the problems of the old environment in a more expensive platform.
Experienced ERP interims lead structured discovery sessions across each key function – finance, operations, supply chain, HR, procurement – with the specific goal of closing the gap between what is documented and what is real. The output is not a process map. It is a frank assessment of current-state complexity: the inefficiencies, the manual interventions, the reporting gaps, the integration points that will require careful handling, and the data quality issues that will need to be resolved before migration is viable.
This work is rarely comfortable. It often surfaces things that people would prefer not to surface. But doing it properly at this stage is significantly less painful than discovering the same issues during testing or at go-live.
Scope definition is where more ERP programmes go quietly wrong than at any other single point. It is also the area where interim ERP experience adds the most immediate and measurable value.
The failure mode is well established. Discovery surfaces more requirements than expected. Functional leads identify additional processes they want the new system to support. The implementation partner – whose commercial interest is not always aligned with a tightly controlled scope – accommodates requests that should have been deferred. The programme that was scoped for 18 months becomes a 26-month programme. The business case that was approved by the board no longer reflects what is being delivered.
Defining scope well requires two things that are genuinely difficult to do simultaneously: enough breadth to deliver meaningful change, and enough discipline to defer what isn’t essential to the core programme. The second of those is harder in practice than it sounds. Every requirement that gets deferred has an internal advocate. Every decision to push something to a later phase creates friction.
Interim ERP specialists bring an independence that makes scope discipline possible. They have no internal political stake in particular processes being included. They can push back on scope additions with the authority of someone who has seen what happens to programmes that don’t, and they can help the steering group understand the real cost of accommodating requests that feel low-risk at the time.
The output of this work is a scope that is specific, achievable, and genuinely understood by the people who have to deliver it – with phasing, timelines, and resource requirements that reflect real delivery experience rather than optimistic planning assumptions.
Selecting the right ERP platform and the right implementation partner are two of the most consequential decisions in the entire programme. They are also decisions that are frequently made under conditions that are not conducive to good judgement.
The vendor selection process, done without independent guidance, tends to favour the organisations that run the best procurement process – which is not the same as the organisations that have the best product fit. Demos are polished. References are curated. Pricing models are complex enough that like-for-like comparisons are difficult. Implementation partners present methodologies that look robust and timelines that look realistic. The organisation selecting the system often lacks the direct experience to distinguish between what is being demonstrated and what will actually be delivered.
Experienced ERP interims change this dynamic. They have seen multiple vendor processes across different sectors, and they know the difference between a compelling pitch and a credible delivery capability. They support the RFI and RFP process by defining evaluation criteria that reflect the organisation’s actual operating requirements – not just its technology ambitions. They challenge supplier claims, probe reference sites with the right questions, and assess implementation partner track records in genuinely comparable environments.
The question they are answering throughout is not which platform has the most functionality. It is which platform, implemented by which partner, can actually be delivered successfully in this organisation, in this timeframe, at this level of complexity. Those are different questions, and conflating them is one of the most common and most costly mistakes in ERP procurement.
ERP programmes cut across almost every part of the organisation. Finance, operations, IT, HR, and procurement all have a stake in the outcome. The steering group includes people with different priorities, different tolerances for risk, and different views on what the programme should deliver.
Without clear governance, this complexity becomes a source of delay. Decisions that should take days take weeks. Escalation routes are unclear, so problems accumulate rather than getting resolved. Priorities clash between functions, and programme leadership lacks the authority or the framework to arbitrate effectively.
Good governance doesn’t eliminate disagreement – it creates the structure needed to resolve it. That means a steering committee with clear membership, defined decision-making authority, and a meeting cadence that matches the pace of the programme. It means reporting that gives leadership a real view of progress and risk, not a presentation designed to avoid difficult conversations. It means escalation processes that are understood before they are needed, rather than improvised when something goes wrong.
Interim programme leaders establish this structure during the planning phase, before the programme enters its more complex stages. The work is largely invisible once it is in place, but its absence is felt quickly and at significant cost.
The financial consequences of a poorly managed discovery and planning phase are well documented, but they tend to be underestimated at the outset because they are deferred. The cost doesn’t appear on the project tracker in month two. It appears in month fourteen, when scope has expanded by 40%, when the implementation partner is managing expectations on delivery timelines, and when the organisation is being asked to approve a revised business case that no longer resembles the original.
By that point, the options are limited. Contracting scope means losing functionality the business was expecting. Extending timelines means extended costs and continued dependence on legacy systems. Changing implementation partners – sometimes the right decision – carries its own cost and delay.
The decisions that create this position were almost all made in the first three months of the programme. A discovery process that didn’t go deep enough. A scope that wasn’t defended when it started to expand. A vendor decision that prioritised the pitch over the proof. A governance structure that was agreed in principle but never properly established.
These are not unusual mistakes. They are the default outcome of running a phase of this complexity without the experience to run it well.
Bringing in the right expertise at the start of an ERP programme is one of the highest-return decisions an organisation can make. The cost of an experienced interim specialist during discovery and planning is a fraction of the cost of recovering from the decisions that phase gets wrong.
Broster Buchanan works with organisations at this critical early stage, connecting them with proven interim ERP specialists — Programme Directors, Transformation Leads, and functional experts — who have delivered complex implementations across private equity-backed businesses and large corporates.
If you are approaching vendor selection, navigating discovery, or building the governance structure for an ERP programme, we can help you identify the right interim resource and give you a clear view of the talent currently available.
Planning an ERP programme?
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Lee Clarke – Senior Business Director
Technology & Business Transformation
