This is a very common question that many advertisers think about when they start thinking about the type and length of ad they want to promote on YouTube. There is a simple answer for this too. It depends. Obviously that is not the answer your were looking for, however it really does depend upon what you’re trying to achieve. If you want to tell a story, then longer might be better but have less of an engagement rate however if you’re looking to get a brand noticed quickly then shorter might be better.
Fortunately the good people at YouTube’s Unskippable Labs put together this great video that talks about just this question. After watching this you should have an understanding of what may or may not work for you. The bottom line is that YouTube is such an amazing advertising tool for you and your brand but it’s still so new that we continually learn things we didn’t know each and every week! Enjoy!