Spreadsheets: Daniel T Li

The Power of Spreadsheets: Unlocking Efficiency with Daniel T. Li

Performance Tips

Overview

1. The Separation of Church and State (Inputs vs. Calculations): Li rigorously advocates for the separation of hard-coded inputs (assumptions) from formula-driven calculations. By isolating variables, he ensures that a change in one assumption cascades correctly through the model without requiring the user to hunt through thousands of cells.
2. Error Trapping and Validation: His spreadsheet designs often feature robust error-checking mechanisms. Rather than allowing a model to output nonsensical data (such as dividing by zero), Li promotes the use of error-handling functions (like IFERROR and ISERROR) to flag issues immediately, acting as an early warning system for the user.
3. Documentation as Code: Li champions the idea that a spreadsheet must tell a story. This involves the extensive use of comments, headers, and color-coding conventions (e.g., using specific colors for hard-coded numbers versus formulas) to make the logic self-evident to a third-party auditor.

Design Categories

: The collection includes comprehensive calculators for concrete design (slabs, columns, shear walls), steel design (purlins, tube columns), and lateral analysis (wind and seismic loads based on ASCE 7 and IBC codes).