As part of Advertising Week New York, YouTube has announced some new ad tools which are designed to provide more capacity to improve response and measure ad performance.
The first addition is an expansion of YouTube's ad 'extensions' tools, which will provide new ways to share expanded context info within your YouTube ads.
As explained by YouTube:
"Soon you’ll be able to make your video ads more actionable with a greater variety of ad extensions. Similar to extensions on Search ads, extensions on YouTube enhance your video ad with additional useful information - giving consumers more reasons to take action."

YouTube advertisers can already add extensions for other information - form and location extensions were both added earlier this year, providing a simple, in-stream way for ad viewers to get more information quickly.

The listings provide more context, which will obviously have varying value, based on your use-case for YouTube ads.
In beta testing, YouTube says that Vodafone has seen good results with its expanded extensions offering:
"Using extensions, Vodafone drove a 2.3x incremental lift in Ad Recall and a 3.5 percent CTR - a 785% increase over their regional benchmark."
I mean, probably don't go in expecting a 785% increase in anything, but extensions could make it easier to drive action from your YouTube ads.
YouTube's also improving its 'Brand Lift' metrics to provide more data on ad response.
"Based on your feedback, soon you’ll be able to set up Brand Lift studies directly in Google Ads or Display & Video 360 and conveniently view reporting alongside your other ad metrics. Additionally, we’ve introduced two new metrics: lifted users, the number of people who were influenced by your ad, and cost-per-lifted-user to make it easier for you to optimize your campaign’s effectiveness and cost-efficiency. To get the most out of these new measurement tools, we recommend using Maximize Lift bidding."
Brand Lift aims to better quantify YouTube ad performance by giving you more insight into exactly who saw your ad content, which can be cross-checked with response data.
And lastly, YouTube's also working with more data partners to improve the verification of its ad performance metrics.
"We're also ramping up our investments in Google Measurement Partners to ensure our advertisers can measure YouTube media with measurement solutions that meet rigorous, verified standards. We work closely with partners to ensure their solutions respect user privacy. In addition to Nielsen Catalina Solutions (NCS) and Oracle Data Cloud, soon CPG advertisers will have the option to measure their YouTube media using IRI. These offerings complement geo experiments with Nielsen MPA, giving advertisers a variety of options for seeing the offline impact of their video ads."
Ad performance data, and data transparency more broadly, are key issues facing the digital marketing sector, so it makes sense for YouTube to provide more verification on this front.
As noted, the new tools have been announced as part of Advertising Week and will be available to all shortly.