Schema.org/Event error: "Event's start date is in the past"

Question

I am testing the URL http://www.songkick.com/artists/4526008-overwerk in the Google Structured Data Testing Tool (quick link).

The schema.org Event (http://schema.org/Event) data structure (mid way down the results) throws the the following warning.

Error: Event's start date is in the past.

How should I resolve this warning/error?

Should events in the past simply not be marked up with structured data? My opinion is that historical event data may provide value somewhere down the line. I have found little on this topic except those points that state it must list "future dates", but does not state anywhere that old events should forgo structured data markup.

Answer 1

I think it's important to differentiate between (1) valid Schema.org microdata/RDFa markup and (2) markup which will be used by Google Rich Snippets.

Google's Structured Data Testing Tool tests to see whether your markup is right for inclusion in Google rich snippets - it doesn't just test whether your microdata/RDFa is valid.

I presume that Google don't show rich snippets for events in the past (because people are generally searching for events they might attend in the future - where's your favourite band playing next, etc), so a past event is not given a rich snippet. So it's throwing a "warning". But that doesn't stop your markup from being fine.

Just because Google doesn't currently show events in the past doesn't mean that you shouldn't markup past events with http://schema.org/Event because parsers other than Google might.

The only actual error I can see in your microdata is the enddate property of the "FESTIVAL ICAM 2014" Event, which should be in the format YYYY-MM-DD - at the moment a code error is setting this as "#{event.iso8601_datetime_with_offset}"