Start a JD system with AC.ID, or PRO.AC.ID?

Hello, new to the Johnny.Decimal system and looking forward to setting it up, but I don’t know whether it’s best to start with just the area/category version or go big with project/area/category numbering.

I have a few projects, and might have more… or I might not. I could make my current filing system fit with the AC.ID format.

Torn between keeping the system simpler, and building it from the start to have room to grow.

I’d start simple and get used to it first.

Going to multiple projects is a conceptually very small jump – just three more numbers, right? – but after running it at work for a while I can tell you that it does add a bit of overhead. I wouldn’t recommend you jump right in unless you absolutely need to.

I ran most of my life with a single JD project for a long time.

And, welcome!


This was the very question I had! In addition to starting simply, I was wondering if anyone ever tried to shoe-horn projects into the AC.ID numbering system. My thinking is that the “Product” or output from a project might be more important to track, which would make it independent of the constraints of project management (file locations, backups, etc.)

It can be done, but you do need to be careful.

Johnny.Decimal itself was 50-59 in my AC.ID system for a long time. I consider it ‘a project’: it’s got inputs (my thoughts, notes), things I was doing (writing, research), outputs (the website, code).

But of course this only works if your project is small — you only get to manage 10 types of things, as your categories — and if you don’t have too many projects, as you’re also limited to 10 of those.

If you need PRO.AC.ID, use it. But really make sure that you need it. Are you really managing multiple projects, or do you just have multiple interests?

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In my mind, everything is a project. That’s problematic unless we dispense with semantics. Multiple interests is closer to the mark, although I really do have a lot of client projects.

The real challenge is the AC.ID is easy to grasp. since I devoured everything you wrote on the subject, it’s stuck in my head as the ideal. (It meshes well with another tool that I use: Workona.) On the other hand, PRO.AC.ID is not intuitive to me.

For example, with PRO.AC.ID, each project could have a similar outline, where AC matches AC. If I want to search for an item, say a bit of reusable code, and I didn’t remember which project contained it, my search would have to include all projects, right?

In other words, if * = wildcard, then my search syntax would be *AC and that would potentially return a lot of results. (Assuming I stored my index in Simplenote.)

Or, am I missing a fundamental tenet of JD?

You haven’t missed anything, it sounds like you’ve nailed it. Especially the idea of matching AC across similar projects, that’s exactly how you should be doing it.

I don’t know if any system can help the situation you describe. You’ve got a bunch of projects, they all contain code in, say, 23, and so you can search for all instances of all code across all projects using *23*. But if the thing you’re looking for could be in any of those, well, you’ve at least narrowed your search (from ‘everything in my system’) which is kinda the point of JD. It gets you from everything to the category where a thing should be.

Don’t forget if you’re in Simplenote or similar you can also add a text string to narrow down the search.

Otherwise I’d suggest creating a new project for ‘re-useable bits of things’ and when you realise that something should be elevated to that level, re-organise.

Let us know how you get on, it’s an interesting challenge. The PRO.AC.ID thing is quite new so I’m still figuring it out. It’s not a solved problem.

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Thanks for confirming my understanding. My next step is to tinker with a simulator, perhaps in Excel, where I configure a raw list of files into AC.ID, using the concepts you outlined in Developing your own system