---
title: "Reid Ji (@reidstonji) | Hashnode"
description: "Building is cheap now. Knowing what to build isn't. Data picks, AI builds, every result goes public — misses included."
url: "https://hashnode.com/@reidstonji"
---

@reidstonji

# Reid Ji

@reidstonji · Hangzhou, China · Joined September 2026

Building is cheap now. Knowing what to build isn't. Data picks, AI builds, every result goes public — misses included.

[Website](https://numberandreason.com/)

### [No method has been shown to predict what software to build. So I'm backtesting mine on three years of store data](https://reidstonji.hashnode.dev/no-method-has-been-shown-to-predict-what-software-to-build-so-i-m-backtesting-mine-on-three-years-of-store-data?utm_source=hashnode&utm_medium=feed)

Update, Oct 9: I wrote this on Sept 29. The first backtest finished on Oct 1. One signal first looked 13x better than random; compared against needs of the same size, it was about 2x; with finer size

7 min read · [reidstonji.hashnode.dev](https://reidstonji.hashnode.dev/no-method-has-been-shown-to-predict-what-software-to-build-so-i-m-backtesting-mine-on-three-years-of-store-data?utm_source=hashnode&utm_medium=feed)

[2](https://hashnode.com/posts/no-method-has-been-shown-to-predict-what-software-to-build-so-i-m-backtesting-mine-on-three-years-of-store-data/6ac83de63ea584ea9edc7f40) [Oct 9](https://hashnode.com/posts/no-method-has-been-shown-to-predict-what-software-to-build-so-i-m-backtesting-mine-on-three-years-of-store-data/6ac83de63ea584ea9edc7f40)