Display QA | Time to visual start

What is Time to visual start, how is it measured and why does it matter?

What is Time to visual start?

Time to visual start is a performance metric that measures the time it takes for an ad to load under repeatable circumstances. It is an aggregate test that is affected by many important individual performance factors such as banner weight, number of assets, code efficiency, serving platform performance and CPU usage.

Why Time to visual start matters

Serving well-performing creatives is important in order to achieve maximum attention from site visitors and ad audiences. Time spent waiting for a creative to load is opportunity for the visitor to focus their attention elsewhere, and might even result in a scroll-by.

High time to visual start numbers are almost always indicative of other underlying performance issues that will force the primary content and other ads to compete for precious visitor resources such as bandwidth and CPU cycles. Long loading times are considered an annoyance by many internet users, no matter whether it is the primary content or the ads that are loading slowly.

We ran extensive tests with our publisher customers, agencies and technology vendors and we determined that there is a clear correlation between lower than expected view-ability numbers reported by 3rd/4th party systems and creatives yielding high time to visual start measurements.

What is it not?

Time to visual start is not a test that provides the exact same answer every time. Its absolute value is not as important as its relative value compared to average creatives. While the check methodology is easily applied in manual checks or other systems, the values gathered are typically not comparable between systems.

High time to visual start values should be used as a suggestion to further investigate a creative as it may be plagued by other performance issues.

How is Time to visual start measured?

Time to visual start is determined by measuring the time it takes for an ad to load its first visual impression, from the time the ad code is loaded into an otherwise blank page. The test is performed 5 times and the median value is used.

Technically, Advalidation does this by screen capturing its validation browsers. From a blank canvas (about:blank), Advalidation will run the creative and start an accurate timer which will stop as soon as the system can see any graphical change – the change can be anything from one single pixel changing colour to the entire creative having loaded — Advalidation makes no distinction.

As with all tests performed by Advalidation, the validation browser starts out with a cleared cache and otherwise empty user profile.

What are good and bad values for Time to visual start?

Advalidation's recommendations in regards to time to visual start values are as follows (these are the result of millions of tested creatives and subsequent data analysis):

• Fast: less than 0.5 seconds
• Normal: between 0.5 and 0.8 seconds
• Slow: above 0.8 seconds

These are reflected in the available fixed settings in the Display ad spec setup. It is also possible to set a custom number.

How to achieve good Time to visual start performance

The most important advice in regards to Time to visual start performance is: less is more.

Here are a few key points:

• Avoid heavy JavaScript frameworks if the functionality you actually use can be provided by more lean custom code or other less bloated libraries.
• Keep the number of assets low by using inline CSS and JS where appropriate and by combining many small PNG images into one PNG sprite.
• Consider that adding scripts from 3rd & 4th party measurement and brand safety providers increase load times and creative weight — often significantly. If nothing else, try to settle for one 3rd party that provides all needed functionality.
• For rich media creatives with video or other heavy content that requires use of polite or subsequent load, always display a placeholder/image version of your message on initial load — as early as possible. The image is then replaced with the rich media content once it has finished loading.

Happy validating!