FINDINGS
6 seconds long bumper ads offer a wide reach, give desired brand results and provide a canvas for creativity in advertisements. 15 seconds long ads being non-skippable, offer a great opportunity for call-to-action (CTA) so that advertisers can optimize viewers' attention. 30 seconds long video ads are more cost-effective as advertisers only pay when viewers watch the video for at least 30 seconds. They also provide viewers with an opportunity to get deeper insights into the featured products, deals, or services.

6 SECONDS BUMPER ADS
 Bumper ads are 6 seconds long, non-skippable YouTube video ads that play before a YouTube video users intend to watch. Since the release of YouTube’s bumper ads in 2016, they have transformed the landscape of YouTube video advertising. Not only these 6 seconds long ads offer a wide reach, but they also render desired brand results and provide a canvas for creativity in advertisements. Some benefits of YouTube's 6-second bumper ads include:

Due to their short length, these ads offer a wide audience reach and are ideal for creating brand awareness. In 2017, Google studied 122 bumper ad campaigns in the United States and found that 70% of these bumper ads resulted in a considerable lift in brand awareness, with an overall average increase of 9%.
When it comes to ad recall, these ads perform even better. Ad recall is a measure of the effectiveness of an ad in which a sample of viewers of a specifically targeted ad are later asked if they can remember the ad. As per Google's global study of 300 bumper ads, 9 in 10 bumper ads drove ad recall, with an average lift of more than 30%.
One of the biggest challenges brands face in advertising is "capturing consumers' attention". By using YouTube's 6-second bumpers, brands such as Busch are addressing this challenge by creating short but contextually-relevant, spot on ads to successfully break through with customers.
Six seconds may seem too less to effectively deliver the message to viewers but since "creativity thrives in constraint", they offer room for creative and more appealing advertising.
YouTube's bumper ad campaigns offer a cost-per-impression (CPM) pricing model where advertisers are charged per 1,000 impressions and the final price varies with competitiveness and targeting. Advertisers have the option to set a maximum CPM and daily budget to keep control of their advertising spend.
Advertisers can run bumper ads as standalone ad campaigns but to increase their effectiveness, Google recommends running these ads campaigns with other long duration TrueView ads, for example by showing a 15-30 second long TrueView ad to new viewers and then showing them bumper ads later or showing bumper ads first followed by a longer TrueView ad.

In a nutshell, these non-skippable, short length bumper ads not only increase the incremental reach of an ad campaign but are also more cost effective as compared to longer video ads. In addition to that, due to the high success and engagement rate of these ads, they can serve as a building block for advertisers' YouTube campaigns. However, advertisers have to be very specific and creative to utilize these 6 seconds effectively.

15 SECONDS LONG ADS
In addition to short bumper ads, YouTube's 15 seconds pre-roll ads are also effective in digital advertising. These pre-roll ads are non-skippable, in-stream ads that play before, mid-roll or after the main content viewers intend to watch. These ads range from 15 to 30 seconds in length, however, the most effective pre-roll ads are between 15 to 20 seconds. Several companies including Geico and Eat 24 have restricted each of their YouTube video ads to 15 seconds and received millions of views. Some benefits of these 15 seconds ads include:

They give freedom to advertisers in their content.
Advertisers can include people, audio, dialogues, products, and other elements to best represent their brand in 15 seconds.
Since these ads are non-skipped, they offer a great opportunity for call-to-action (CTA) so that advertisers can optimize viewers' attention.

30 SECONDS LONG ADS
 TrueView ads, another type of YouTube ad campaigns, are standard video ads for which advertisers pay only when the viewers watch or interact with their ad. There are both skippable and non-skippable TrueView ads of variable length. Skippable TruView ads play for a 30-second duration before or during the main content video allowing viewers to skip them after 5 seconds. While the most effective TrueView ads are non-skippable ads of 15 to 20 seconds duration, a 30-second YouTube ad also offers a number of benefits such as:

In a 30-second ad, brands and other advertisers have enough time to incorporate a short story, tagline, product info, etc. to convey their message.
An ad campaign with a 6-second bumper ad only generates early buzz by allowing advertisers to quickly introduce their brand to the viewers, engaging them, and building brand awareness and trust. However, after creating the foundation of brand awareness by a bumper ad, launching a 30-second ad provides consumers an opportunity to get a deeper insight into the featured products, deals, or services.
As compared to TV ads, viewers reported 38% higher brand awareness as well as 31% higher brand recall after watching YouTube's 30-second TrueView ad.
With a TrueView ad, advertisers only pay when viewers have watched the video for full duration or at least 30 seconds, advertisers still get the ad impressions even if viewers skip the video.
Although a 30-second ad is still short to engage viewers, it is long enough for viewers to decide to skip after they have watched enough.

However, a 30-second video will not be effective if the viewers skip it after 5 seconds and therefore, advertisers need to treat the first 5 seconds of a skippable 30-second video ad just like a bumper ad.

ADS MORE THAN 30 SECONDS LONG
Although YouTube allows skippable TrueView ads to be as long as 6 minutes in length, due to shorter attention time span of viewers, video ads of more than 30 seconds are less likely to yield viewers' engagement unless viewers are forced to watch them before or during a YouTube video. Neverthless, studies have found that pre-roll ads of up to one-minute are effective as long as they’re creative and engaging. Ads more than 30 seconds provide consumers an opportunity to get a deeper insight into the brand as well as featured products, deals, or services.

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