diff --git a/principles.qmd b/principles.qmd
index dcbcbc6..e804bec 100644
--- a/principles.qmd
+++ b/principles.qmd
@@ -3,9 +3,14 @@
 - Before developing the package
   - scope
   - how it fits within the ecosystem
+-   classes (they are deffined in omopgenerics)
 -   error messages
     -   Why?
     -   How?
 -   naming
     -   functions
+      -  strcutures: `generate...CohortSet`, `...Cohort`, `add...`, `summarise...`, `plot...`, `table...`, 
     -   arguments
+- input validation
+- testing
+- reexport