Searching, sorting, and “Inbox Zero”

Two fundamental computer science problems that anyone who’s studied the topic will recognize are searching and sorting. These are intuitive enough at a high level:

  • Search algorithms scan a bunch of data to find what you’re looking for
  • Sorting algorithms take a bunch of data and re-arrange it into some order (that may be alphabetizing, grouping, labeling, whatever)

We use these principles outside the classroom as well. Consider email. The modern “knowledge worker” is inundated with emails, and there’s a certain subculture that constantly strives for “Inbox Zero” as a solution to the problem. I would argue that’s not the optimal strategy for most people, most of the time.

Inbox Zero is a strategy that’s heavy on sort and light on search. You want to classify emails, put some in folders, capture the information from as many as necessary, and delete as much as possible. That’s often useful, but a little bit of upfront work can handle a lot of that for you, and when you take those steps the Inbox Zero approach becomes much less attractive than it superficially appears.

As an example, here’s my strategy, which consists of a couple of sorting strategies and then (mostly) letting search handle the rest.


The first sorting mechanism I have is the simplest one: unsubscribe to as many lists as you can. That’s great and for most commercial services I’ve done it, but I also receive emails from…

  • the Beowulf cluster mailing list
  • auto-pay services
  • the Earlham CS admin mailing list
  • the Earlham faculty mailing list
  • the ECCS GitLab instance if someone pushes an update
  • our wiki when someone makes a change

I don’t need every single message in all of those categories, but I know I’ll need or want some of them, so I can’t just delete them. That’s where filters come in.

I rely on (entirely too many) email filters on my Mac Mail client to handle preprocessing for me. Each filter applies a set of rules to incoming emails based on certain information in the email, often sender or subject contents. It takes many minutes/few hours to set up initially, but adding to it incrementally is quick and simple after. For that reason, it’s most of the sorting I ever do.

Those two tactics – cutting subscriptions and running filters – account for all of the sorting I do more than once every couple of months. That’s because I want the power of…


The major downside of deleting emails (especially if you then clear the trash, as I imagine most Inbox Zero people want to do) is that you can no longer search the content. Even if you think you’ve written everything down and downloaded every document, there’s a chance that something you consider unimportant now will become important later. Your ability to remember the context of an exchange depends on how well you’ve captured the details in your notes, and you may not know all the details you need for a long time.

The ability to search every message a human being has sent me in the last several months is handy. It’s not something I do all the time, but it has high value on the occasions when I do it. I’ve recovered many documents, resolved ambiguities during meetings, and revived forgotten but important conversations by doing this.

Why Inbox Zero?

Space is cheap, (human) time is expensive, search is extremely useful, sorting is only modestly useful… and yet we spend a lot of human time rearranging messages. Why?

I think the answer is obvious: It looks and feels nice to have a squeaky-clean inbox. An inbox full of messages feels like clutter, and clutter is a stressor.

That’s a perfectly valid reason! It’s why, a couple of times a year, I reach for Inbox Zero myself. I’ll apply a bunch of sorting to my inbox: deleting, archiving, moving things to new folders, etc. It’s just not necessary most of the time. My attention, like most people’s, is much better devoted to getting work done than to maintaining a clean inbox.

Most of the time, I’m happy to search 773 emails rather than sort 773 emails. Go to Inbox Zero because you want to, not because you think you must.

UPDATE: I promise I wrote and scheduled this post before I saw the most recent (Friday July 26) XKCD cartoon but I’m happy with the serendipity: