Board Thread:Comics/@comment-1398253-20200116154714/@comment-18172179-20200116173951

Several online sources identify 'Detective Comics #38' being published on March, 1940. 'Batman #1' on the other hand, is almost always identified as being published on April, 1940; or at least late March, 1940.

The point is, Detective 38 IS Robin's first appearance because it was published first.

The dates on the infoboxes are always COVER dates, which is very different from publishing dates. And it makes things worse that back in the 40's, the system was radically different than today. The infobox is wonky in that regard.

In other words, ignore the infobox and check the notes sections for both issues.