chore(contrib): link to prioritization method

Author: mharrisb1

CONTRIBUTING.md

@@ -28,38 +28,7 @@ The roadmap is just a ranking of the currently open issues and no hard dates are
 
 I have added version release milestones to some of the issues to give a sense of what is coming in what order. View milestones [here](https://github.com/mharrisb1/openai-responses-python/milestones).
 
-I (Michael) am the BDFL of the project and can and will arbitrarily rank issues according to my own needs (and those of my [employer](https://www.definite.app)) but for the most part I try to evaluate priority of issues based on a 2-dimensional system that looks at **_effort_** and **_impact_**.
-
-- _Effort_ is a rough estimate of whether something will take a lot of work, some work, or little work to implement
-- _Impact_ is a rough estimate of how important something is
-
-Both are unscientific and flawed but they allow me to try to focus on what to work on when.
-
-If you look at the [project's issues](https://github.com/mharrisb1/openai-responses-python/issues), you'll see they are labeled with some non-standard issue labels.
-
-| Label                                                                                | Description   |
-| ------------------------------------------------------------------------------------ | ------------- |
-| <span style='background-color: green; padding: 2px; border-radius: 5px'>e0 🌵</span>  | Low effort    |
-| <span style='background-color: yellow; padding: 2px; border-radius: 5px'>e1 ⚡️</span> | Medium effort |
-| <span style='background-color: red; padding: 2px; border-radius: 5px'>e2 🔥</span>    | High effort   |
-| <span style='background-color: green; padding: 2px; border-radius: 5px'>i0 🌵</span>  | Low impact    |
-| <span style='background-color: yellow; padding: 2px; border-radius: 5px'>i1 ⚡️</span> | Medium impact |
-| <span style='background-color: red; padding: 2px; border-radius: 5px'>i2 🔥</span>    | High impact   |
-
-Ranking is evaluated according to this quadrant where the priority is ordered from top to bottom and left to right.
-
-```mermaid
-quadrantChart
-    title Issue Ranking
-    x-axis Low Effort --> High Effort
-    y-axis Low Impact --> High Impact
-    quadrant-1 Medium Priority
-    quadrant-2 Highest Priority
-    quadrant-3 Low Priority
-    quadrant-4 Lowest Priority
-```
-
-View ranked [open issues](https://github.com/users/mharrisb1/projects/4) and [in progress](https://github.com/users/mharrisb1/projects/4/views/2) issues.
+I (Michael) am the BDFL of the project and can and will arbitrarily rank issues according to my own needs (and those of my [employer](https://www.definite.app)) but for the most part I try to evaluate priority of issues based on an [Impact-Effort Analysis](https://github.com/mharrisb1/iea).
 
 ## Setting up development environment