Rebuilding an Excel model

The six workbooks in the examples were rebuilt with the same method. It works for any FAST-style model and most models that are not.

1. Import the inputs. Import (planned) reads the input sheets. Single values go to inputs.rfn with their labels and units. Every block with rows and columns (S-curves, rate curves, traffic counts, supplier quotes) goes onto its own sheet of the data workbook, and the matching table lines are written for you. It also writes a sheet map as a starting checklist.
2. Write the timeline. Read the Timing or Flags sheet: the start date, the phases, the column width in each phase, and the fiscal year end. Custom flags (tenor, grace, gate opening) become window lines.
3. Rebuild one sheet at a time, top to bottom. Start with operations and revenue, then construction, funding, debt, tax, the waterfall and the statements. Each block of rows usually becomes a few lines.
4. Replace copy-paste pairs with solve. Every “- copy / - paste” row pair on a Solve sheet is one solve line.
5. Move checks across. Each check on the Checks sheet becomes a check or alert.
6. Reconcile. Add a reconcile block for the key outputs (CFADS, debt balance, tax, equity cash flows), build, open in Excel and solve. Fix any differences until all are zero.
7. Retire the workbook. From then on, change the source files and build a new workbook.

Patterns found in the six workbooks