# Pairwise Glicko ranking for your notes

Easily sort notes by any subjective criteria.

Rating something on an arbitrary five-star scale is hard - what happens when you find something better? Do you have to readjust your old ratings?

Pairwise comparisons avoid the ambiguity of absolute ratings and create a dynamic ranking that adjusts as you add more comparisons. Just ask yourself "which of these two notes wins?" and the rest is calculated for you.

### Learn more about yourself and your preferences by seeing how you rank your own notes. Try these ideas in seconds:

- Which book or movie is really your favourite? Rank your **Books#Read** or **Movies#Watched** Bases.
- Which project ideas are most worth pursuing? Rank your **#idea** tag.
- Which purchase is the highest priority for you right now? Rank your **#to-buy** tag.
- Which experiences, restaurants, hikes, or travel destinations should you explore next? Rank your **Places** Base.
- Which people should you cut from your life?\* Rank your **People** Base. _Ooh, spicy!_

![colour_base_example](docs/images/colour_base_example.webp)

_Other comparison arena UI options are available in Settings - shown here is **right-split**, useful if you'd like to watch your Base update as your ranks change, but I personally use **new window/popout**_. Mobile devices are supported by an additional single-note layout type for phones with smaller screens.

## How it works: Try it in two minutes

1. Install from [Pairwise Glicko Ranking - Obsidian Community Plugins](https://community.obsidian.md/plugins/pairwise-glicko-ranking).
2. Run the **Pairwise Glicko Ranking: Start rating session** command (or click the trophy icon)
3. Pick a **cohort** of notes to rank (vault, folder, tags, or Bases).
    - The plugin opens **two notes side-by-side** and you choose a winner.
    - The plugin (optionally) writes stats like **Rank** (1 = best in cohort), **Rating** , or **Wins** to frontmatter (property names are configurable).
    - Your Bases can then sort or filter by those properties, so you can rank notes by subjective criteria without having to decide what star rating a note "deserves".

## Overview

- Define the cohort of notes to rank - works especially well with **Obsidian Bases**: pick a **Base** and a **view** to define your cohort dynamically
- Efficiently review and pick a winner with keyboard shortcuts and an unobtrusive on-screen bar
- Per-cohort stats and rankings can be written to frontmatter
- Information-gain matchmaking that automatically picks the most useful pairs to compare
- A stability progress bar that shows how close your rankings are to converging
- Glicko-1 rating updates - uncertainty (sigma) governs step sizes automatically, so new notes converge fast and experienced notes stay stable
- Robust to note renames and moves via stable per-note IDs
- Cohorts are saved so you can resume ranking sessions, picking up where you left off

## Workflow

### 1. Start a session

![cohort_creator](docs/images/cohort_creator.webp)

- Click the trophy icon in the left ribbon, or run the command **"Pairwise Glicko Ranking: Start rating session"**.
- Create a cohort (the set of notes you're ranking together) in the picker:
  - Vault: all Markdown notes
  - Base: notes returned by a specific **Base** and a specific **view**
  - Folder: a single folder, with or without recursive subfolders
  - Tag (any): notes that match any of the selected tags
  - Tag (all): notes that match all of the selected tags
  - Previously saved cohorts appear here too

Saved cohorts can be renamed and reconfigured in Settings. If the folder or Base that defines a cohort is later moved or renamed, the plugin will prompt you to point it to the new location to safely migrate your saved ratings.

### 2. Compare two notes

![arena](docs/images/arena.webp)

Two notes open side-by-side in Reading mode for you to compare. Use the arrow keys on your keyboard or the buttons on the session bar to choose a winner.

- Left Arrow: choose left
- Right Arrow: choose right
- Up or Down Arrow: draw
- Backspace: undo last match
- Escape: end the session

A toast shows the winner after each comparison (toggle in Settings).

### 3. End the session

Press Escape or run **"Pairwise Glicko Ranking: End current session"**. If you've enabled a Rank property for this cohort, the plugin recomputes ranks across the cohort and writes them to frontmatter.

Optionally, the plugin can generate a **post-session report** - a Markdown note summarising the session (biggest gains, losses, surprises, leaderboard snapshot, match log, and more). Reports use a template with `{{glicko:...}}` placeholders that you can customise, or you can use the built-in default. Run the command **"Generate example report template"** to create a starting template you can edit. Report generation is configurable per-cohort and globally in Settings.

## Frontmatter

The plugin can write the following properties to frontmatter (configurable per-cohort, all optional, names customisable):

- Rating
- Rank (1 = highest within the cohort)
- Matches
- Wins
- Uncertainty (sigma)

You can then use the values computed by the plugin however you want. For example, enable the Rank property and then sort a Base by it to see your notes in ranked order, or use the Rating property to filter for your best notes with a rating above a certain threshold.

**Tip:** Configure global defaults in Settings, and (optionally) set per-cohort overrides when creating or editing a cohort.

![cohort_options](docs/images/cohort_options.webp)

## Settings overview

- Winner toasts
- Where to store note IDs: frontmatter (default) or end-of-note comment
- Note ID property name (default: `glickoId`)
- Progress bar settings (stability threshold, surprise highlight)
- Default frontmatter properties (names and which to write)
- Ask for per-cohort overrides when creating a cohort (on by default)
- Post-session reports: enable/disable, report folder, file name template, and custom report template path
- Cohorts section: rename a cohort and change its frontmatter, scroll, and report overrides. The plugin can preview and perform bulk updates (write, rename, remove) across the cohort.

## Mobile support

The plugin is fully functional on mobile devices, with support for all desktop layouts on tablets (except popout/new window), and an additional single-leaf layout for phones that allows comparison between two notes using a switch button.

![colour_base_example_mobile](docs/images/colour_base_example_mobile.webp)

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If you've made it this far: start a session, pick a small cohort, and do a dozen comparisons. You'll be surprised how quickly a meaningful order appears.

\*Disclaimer: I have not used this plugin to end any friendships. If you try it out, please let me know how it goes! Although I accept no responsibility for any fallout. :)