Understand your Brand Lift measurement data - Display & Video 360 Help [gg-displayvideo-en]

Understand your Brand Lift measurement data

Brand Lift uses data from surveys to measure how your ads influence people. You can set up Brand Lift to show surveys to people about your product or brand.

In order to accurately detect your lift, a certain number of survey responses is required.

How Display & Video 360 measures your Brand Lift

Display & Video 360 can narrow down how much lift your Brand Lift metric generated based on the amount of positive survey responses between people who have seen your ads and those of people who were withheld from seeing your ads. Generally, more responses are required in order to accurately detect smaller amounts of absolute lift. Before your lift is detected, you will be able to see an estimation of it based on your response count.

When to expect detectable lift

View the following guidelines about how many responses are required to detect your lift.

1. For high-performing line items, you can expect to detect lift once you receive about 2,000 responses per lift metric.
2. At the recommended budget minimum, you can expect to detect lift once you receive 5,600 responses per lift metric.
3. If your line item has not shown any lift after reaching 16,800 responses per metric, you may not be able to detect your lift.

Note: In general, you may start seeing lift results once your surveys reach 2,000 responses.

Required total responses for measuring Brand Lift

In order to measure Brand Lift accurately at various levels, the total response count must be within a certain range. The smaller the absolute lift, the more survey responses are required to ensure accuracy. The table below shows the required total response, given a detectable absolute lift:

Detectable absolute lift	Required total response count
> 4%	1,200 ~ 2,800
3%	2,800 ~ 5,000
2%	5,000 ~ 11,000
1.5%	11,000 ~ 20,000
1%	20,000 ~ 45,000
0.5%	45,000 ~ 180,000
< 0.5%	> 180,000

 

Example

For detectable absolute lift percentages not mentioned in the chart, you may need to estimate to find the total required response count.

Let's say you have .75% absolute lift and want to know the number of responses you need to detect the absolute lift. 45,000 responses would be more than what you need (since the minimum requirement to detect .5% absolute lift is 45,000 responses), while 20,000 responses wouldn't be enough (since the minimum requirement to detect 1% absolute lift is 20,000 responses).

Since .75% is halfway between 1% and .5%, you would need roughly between 20,000 and 45,000 responses to get .75% detectable absolute lift (or about 33,000 survey responses).

If your Brand Lift metric's absolute lift approaches 0, more survey responses are required to accurately measure absolute lift. This is because if there's only a small difference between the responses of people who have seen your ads and those of people who have not seen your ads, more responses are required to determine exactly what difference there is.

Brand Lift metrics

Absolute brand lift

This metric shows the difference in positive responses to brand or product surveys between the group of people who saw your ads (the exposed group) and the group withheld from seeing your ads (the baseline group). This metric is calculated by subtracting the positive response rate of the baseline group from the exposed group. Absolute brand lift measures how much your ads influenced your audience's positive feelings towards your brand or product. For example, an increase from 20% to 40% in the positive survey responses between the two surveyed groups represents an absolute lift of 20%.

Absolute brand lift and insertion order performance

Absolute lift doesn't necessarily reflect your overall brand lift performance. It is better to focus on a metric like cost-per-lifted user as the primary success metric of your insertion order, because it factors in both reach and cost. See the following table:

Insertion Order	Cost	Cost per 1,000 impressions (CPM)	Reach	Absolute lift	Lifted users	Cost-per-lifted user
Insertion Order 1	$100	$15	6,666	10%	667	$0.15
Insertion Order 2	$100	$5	20,000	5%	1,000	$0.10
Difference	n/a	66%	200%	50%	60%	33%

If you consider absolute lift only, Insertion Order 1 appears to perform better than Insertion Order 2. However, at the same cost, Insertion Order 2 drove 50% more lifted users, at a 66% lower CPM, and with a 33% more efficient cost-per-lifted user.

Headroom lift

The impact your ads had on increasing positive feelings towards your brand or product compared to the positive growth potential your brand or product could have gotten. This metric is calculated by dividing absolute lift by 1 minus the positive response rate of the baseline group. For example, an increase from 20% to 40% in the positive survey responses between the exposed group and the baseline groups represents a headroom lift of 25%.

Relative brand lift

The difference in positive responses to brand or product surveys between users who saw your ads, versus users who were withheld from seeing your ads. This difference is then divided by the number of positive responses from the group of users who didn't see your ads. The result measures how much your ads influenced your audience's positive perception of your brand. For example, an increase from 20% to 40% in the positive survey responses between the two surveyed groups represents a relative lift of 100%.

Since survey responses can't be collected for the entire exposed and the baseline groups, this data is extrapolated from the responses that have been collected, which gives you an estimated number within a certain range. Usually, the confidence interval is 90%, so you can expect that in 90% of the cases, the true lift number will be within that range (if you were to have reached everyone).

Baseline positive response rate

How often users who were withheld from seeing your ads responded positively to your brand. Use this metric to better understand how positive responses to your brand were influenced by general media exposure and other factors, not by seeing the ads.

Exposed survey responses

The number of survey responses from people who saw your ads.

Note: If you see a low number in this column, that indicates that there aren't enough survey responses yet. Continue running your line items and check back soon.

Baseline survey responses

The number of survey responses from people who were withheld from seeing your ads.

Note: If you see a low number in this column, that indicates that there aren't enough survey responses yet. Continue running your line items and check back soon.

Positive response rate

Out of all the people who responded to the survey, this is the percentage of people who responded with a positive answer in regards to your product or brand.

Confidence interval

This is the estimated range in which your relative brand lift and absolute lift estimates fall. For example, you may see your relative lift is 38.41%, the point estimate. In brackets you will see the confidence interval from at least 30.5% to at most 45.0%.