The　hydraulic　conductivity　of　naturally　sedimented　and　reconstituted　clays　is　often　interpreted　using　the　settlement–time　curves　measured　from　consolidation　tests.　Understanding　the　accuracy　of　the　interpreted　hydraulic　conductivity　is　essential　in　geological　and　geotechnical　engineering.　To　the　best　knowledge　of　the　authors,　such　a　work　has　been　little　reported　up　to　now.　This　study　aims　at　investigating　the　errors　of　the　interpreted　hydraulic　conductivity　via　the　comparison　between　the　interpreted　values　and　the　measurements.　The　ratios　of　the　interpreted　values　of　hydraulic　conductivity　over　the　measurements　are　examined　based　on　the　data　from　the　consolidation–hydraulic　conductivity　tests　performed　in　this　study　in　conjunction　with　those　published　by　our　research　team.　The　investigated　clays　cover　wide　geological　origins　and　depositional　states.　The　geological　origins　and　depositional　states　are　linked　with　the　errors　of　the　interpreted　hydraulic　conductivity　for　understanding　the　roles　of　these　factors　in　the　uncertainty　of　the　interpreted　hydraulic　conductivity.　The　causes　responsible　for　the　discrepancy　in　hydraulic　conductivity　between　the　interpretations　and　the　measurements　are　identified.　The　probability　distribution　of　the　errors　of　the　interpreted　hydraulic　conductivity　is　also　investigated.　©　2020　Elsevier　B.V.