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diff --git a/data_submission/clin_biospec_assay.md b/data_submission/clin_biospec_assay.md
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--- a/data_submission/clin_biospec_assay.md
+++ b/data_submission/clin_biospec_assay.md
@@ -1,5 +1,5 @@
 ---
-order: 995
+order: 994
 ---
 
 # Submitting Assay Data and Metadata
diff --git a/data_submission/dates.md b/data_submission/dates.md
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+---
+order: 995
+---
+
+# What is the index date?
+
+HTAN cannot accept dates because they are considered Protect Health Information (PHI). In order to obfuscate dates, they should be converted
+to days from an index date.  In this case, the index date is the participant's date of birth.  For example, a participant's therapy start date 
+would be recorded as 365 days if the therapy took place 365 days after a participant's date of birth.
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