When data show a clear trend, DID with state‐specific trends can produce more convincing results (Angrist & Pischke, 2008 ; Besley & Burgess, 2004 ).
1
—
—
When data show a clear trend, DID with state‐specific trends can produce more convincing results (Angrist & Pischke, 2008 ; Besley & Burgess, 2004 ).