An estimated 65% cut in manual road-costing time for Tanzania's National Construction Council

Tanzania’s National Construction Council establishes the base unit rates and costs for road construction and maintenance across all of mainland Tanzania. Government agencies budget real projects against those rates, so when the rates are slow to produce or hard to reach, allocation decisions wait. The entire costing workflow ran on Microsoft Excel. Working under a sub-contracted engagement, I joined the delivery team as Business Analyst and Quality Assurance lead to move that workflow onto a web platform, now live at cces.ncc.go.tz. By my estimate, the change cut manual calculation time by around 65%.

The challenge

The Excel models were not wrong. That is worth saying first, because it shaped the whole project: NCC’s engineers had encoded the costing methodology correctly, and any replacement had to reproduce their numbers exactly, not approximately.

The problems were everything around the calculations:

• Expertise lock-in. Producing an estimate required engineering knowledge of the spreadsheets themselves. The non-engineering users who depend on these rates for budgeting had no visibility into the numbers.
• Access. The spreadsheets lived on specific machines. Users in remote regions had no practical way to reach current rates.
• Maintenance. Construction material prices are volatile and vary by region. Every price movement meant manual edits across regional spreadsheets.

The approach

I had two jobs on this team, and they were deliberately paired: specify exactly what the system must compute, then prove that it computes it.

Business analysis. I worked through NCC’s existing Excel-based costing methodology and translated the engineering-domain requirements into technical specifications the developers could build against: construction resource libraries covering materials, labour, and equipment; construction methods linked to those resources; regional pricing variations; and the rate computation formulas that tie it all together. Most of this work was translation in the literal sense: sitting between civil-engineering logic and software architecture and making sure nothing was lost in either direction.

Quality assurance. Because the Excel models were the ground truth, QA on this project meant reconciliation as much as functional testing. I designed and executed test cases that checked the platform’s output against the original Excel calculations across every region and every construction activity type, and validated data integrity on every computation path. A costing platform that is 99% right is a budgeting liability, so the bar was exact replication.

Post-implementation support. After delivery I stayed on as the primary system maintainer for the six-month support period: updates, bug fixes, user support, and the regional data updates that follow every material price change. Maintaining the system I had specified and tested closed the loop: the same regional price volatility that motivated the project became a routine data update instead of a spreadsheet-editing exercise.

The platform itself was built by the team in Angular over a Java Spring Boot API on PostgreSQL.

The outcome

The system is live and operational at cces.ncc.go.tz.

• Manual calculation time for construction cost estimates dropped by roughly 65%. Computations that previously required Excel expertise from an engineer now run automatically. That figure is my own estimate from the engagement rather than a client-audited measurement, and I label it accordingly.
• Base unit rates for all administrative regions of mainland Tanzania now sit on one web platform, reachable from any device. Users search and filter by construction activity, method, region, and tender mark-up, with no engineering background required.
• Contractors and agencies can upload a Bill of Quantities and have unit rates auto-populated from the system’s established rates, replacing line-by-line manual pricing.
• Regional material pricing is updated centrally in the system as prices move, instead of through edits scattered across regional spreadsheets.

For me this project is a useful counterexample to the idea that consulting value only comes from writing code. The code was written by a capable team; my contribution was making sure the system computed the right things and proving that it did. For a platform the government budgets against, that is the part that cannot be allowed to fail.