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# twinBASIC's 100% Compatibility Goal
- URL: https://nolongerset.com/twinbasics-100-compatibility-goal/
- Published: 2021-04-17T03:26:47.000Z
- Updated: 2026-05-08T13:05:17.000Z
- Description: The difference between 100% compatible and 99% compatible is way more than 1%.
- Author: Mike Wolfe
- Tags: twinBASIC, #Import 2026-05-20 02:59

*To learn more about [twinBASIC](https://www.twinbasic.com/), join me at this year's virtual [Access DevCon](https://nolongerset.com/join-me-at-access-devcon-2021/) where I will be presenting this exciting new project from vbWatchdog creator, Wayne Phillips.*

### Backwards compatibility for the win

Here are the first two sentences from the [twinBASIC website](https://www.twinbasic.com/) (emphasis mine):

> twinBASIC is a modern version of the classic BASIC programming language. With twinBASIC we aim for **100% backwards compatibility** with existing VB6 and VBA projects.

You can inject that backwards compatibility talk [straight into my veins](https://nolongerset.com/reverence-for-backwards-compatibility/).

### The Pareto principle

Why is 100% backwards compatibility so important? The [Pareto principle](https://en.wikipedia.org/wiki/Pareto%5Fprinciple).

Also known as the 80/20 rule, the Pareto principle tells us that we're likely to spend 80% of our time on 20% of the code. That means that even small inconsistencies between VBA and twinBASIC will drastically increase the time required to migrate code. *Any* inconsistency will result in friction in the development process. And if there's *any* friction in the process, it will discourage developers kicking the tires on twinBASIC.

Or, to put it more succinctly:

> **The difference between 100% compatible and 99% compatible is way more than 1%.**

No pressure, Wayne. 😉

*Image by [Gerd Altmann](https://pixabay.com/users/geralt-9301/?utm%5Fsource=link-attribution&utm%5Fmedium=referral&utm%5Fcampaign=image&utm%5Fcontent=1165990) from [Pixabay](https://pixabay.com/?utm%5Fsource=link-attribution&utm%5Fmedium=referral&utm%5Fcampaign=image&utm%5Fcontent=1165990)*