diff --git a/notsof.md b/notsof.md
index f945599ea..7a22a40b7 100644
--- a/notsof.md
+++ b/notsof.md
@@ -94,6 +94,5 @@
 - [[domain]] is the totaility of possible forms within the cognitive reach of the designer
 - [[probabilities]] enter the stage! Finally. They seem to make sense in this context.
   - as usual, when probabilities are independent all's nice and well.
-  - correlation coefficient: 
-   
-![](assets/2021-04-14-13-11-35.png)
\ No newline at end of file
+  - [[pearson correlation coefficient]] 
+   
\ No newline at end of file
diff --git a/pearson-correlation-coefficient.md b/pearson-correlation-coefficient.md
new file mode 100644
index 000000000..b4f576d9f
--- /dev/null
+++ b/pearson-correlation-coefficient.md
@@ -0,0 +1,6 @@
+# pearson correlation coefficient
+
+- [[wp]] https://en.wikipedia.org/wiki/Pearson_correlation_coefficient
+  - [[go]] [[wp]]
+  - [[notsof]] ![](assets/2021-04-14-13-11-35.png)
+