From Case Study Practice to Reality: Building Consultancy Skills to Apply on the Job
Case Study Practice is widely encouraged for students preparing for consulting roles and there is no shortage of resources to learn from. This edition of Deecon-Struct showcases:
How a widely-known case study framework translates into delivery
Additional capabilities that are not always emphasised in preparation manuals but are frequently used at Deecon
The graduate market context explains why disciplined preparation matters. Competition for early career roles has intensified: UK employers reported more than 1.2 million applications for just under 17,000 graduate vacancies. In 2024, the average employer reported receiving 140 applications per graduate job, a 59% increase on the previous year, with financial and professional services among the most competitive [1]. These are the highest volumes in over three decades of tracking. Additionally, the growing population of young people in the UK classified as NEET (‘not in education, employment, or training’) highlights the intensity of competition for roles.
The result is a market where structured thinking and clear communication are necessary – firstly to stand out, and later to deliver.
A Familiar Framework in Action: Market Sizing
Case Study Practice trains students to conduct Market Sizing, deconstructing a market into verifiable drivers and quantifying with defensible assumptions.
In reality, most markets have already been sized, but forecasting is another way in which skills developed from Market Sizing activities can be demonstrated. This is frequently conducted at Deecon during Research and Strategy projects. For a PE Investment firm, Deecon delivered cutting-edge insight on the development and future of both the Fibre and 5G markets.
Deecon sized the Fibre and 5G opportunity using a bottom‑up model that segmented the market by rural and urban premises, then layered in supplier mix, rollout pace, and near‑term coverage ceilings created by build‑rate constraints. We assessed barriers to adoption, rural to urban cost‑to‑serve differences, and incorporated funding priorities and policy dependencies. Current penetration was benchmarked against the population and premises base to quantify the remaining addressable market. All assumptions were explicitly stated and tested through scenario and sensitivity analysis to produce a forecast.
Market Sizing exercises do not have defined answers and may be for markets that either do not yet exist or that are very nascent. The value that consulting can provide is in making the initial forecasts and predictions, to influence key financial decisions.
Beyond Case Study Practice
Additionally, there are capabilities that are not always emphasised in preparation manuals but are used frequently at Deecon. Examples include:
Value mapping and process mapping
Case study resources may introduce the concepts of process and value mapping to graduates preparing for interview; Deecon teams conduct this in practice.
Process mapping is a valuable technical skill employed across many industries, not just consulting. At Deecon, we regularly use this in procurement, supply chain optimisation, operating model design, and systems implementation projects.
In one project, Deecon evaluated SNRG’s operating model ahead of expected annual growth, using value mapping and process mapping. The work addressed bottlenecks in areas such as document control, frontend screening, process formalisation, and data flows with the primary supply chain partner. A systems validation workstream reviewed SNRG’s incumbent systems to identify areas for efficiency optimisation to ensure that new processes were embedded and auditable. This case demonstrates how Deecon converted structured analysis into sustained operational impact.
During a different project at Transport for London (TfL), the same disciplines underpinned procurement and supply chain improvements. Deecon supported TfL’s Capital Delivery function to optimise how the procurement and supply chain team captured benefits across multiple portfolios, including London Underground and Surface transport.
Working through a structured improvement programme during the COVID period, when revenue pressures heightened the need for cost control, the team ran targeted stakeholder workshops to understand current processes. The input from these workshops were converted into process maps.
Deecon used these process maps to identify pain points and improvement opportunities. From this, the team developed recommendations to strengthen capital management disciplines and establish rigorous benefits tracking, aligned to TFL’s overarching Business Plan. For each improvement area, Deecon produced clear business and systems requirements to ensure delivery activity remained traceable to strategic objectives, and conducted user impact assessments to derisk change.
Tendering
Tendering is an example of where familiar case study techniques mature into an evidence led, multistakeholder process that creates durable value for clients and suppliers.
The process starts with strategy development and aims to create frameworks which enable sustainable partnerships, outline how value will be measured, and secure benefits that accrue over a multiyear horizon rather than at a single price point.
One of Deecon’s largest procurement projects was working with Openreach to develop and deliver the sourcing strategy and procurement for the Openreach Network Services Agreement (ONSA), a new framework contract for engineering field services. At the time, ONSA was the largest ever tender for engineering works in the UK telecommunications sector, with a value of circa £3.5 billion from 2019 - 2024. The process of running a successful tender is built upon the essential skills of conducting due diligence, structuring problems to find solutions, and working collaboratively with stakeholders to reach a joint resolution.
Why is Case Study Practice Relevant?
Case study preparation develops habits that consultants use every day. Successful project delivery relies on a set of core skills to make decisive, evidence based judgements, foster collaboration, and produce clear documentation. Applicants to Deecon are advised to review our published case studies to identify the delivery skills applied in project work and to reflect on where they have practised similar skills.
Although the interview setting can feel removed from the realities of client work, the underlying disciplines translate directly into practical action and structured analysis. Above all, consulting is a people-based business. Meaningful progress depends on working collaboratively, building trust, and showing up as your authentic self, so that you can connect effectively with colleagues, suppliers, and clients.
Disclaimer: This article does not provide interview advice or disclose Deecon’s interview process. It illustrates how familiar case study techniques are applied on real client work, alongside additional skills Deecon teams rely on day-to-day.
Words by Mma Ezeonyeasi
Edited by Kate Randall