2015-03-09 16:23

How to select websites for ad campaigns?

In order to plan online campaign impressions optimally, one should know which websites are visited by the individuals making up the target group. By employing the right indicators, the advertising message can be effectively conveyed to consumers of the desired socio-demographic characteristics. What is the proper indicator, then?

Media houses, advertising agencies or advertisers, all need reliable data that could serve as a vehicle for the communication targeted to specified group of internet users. Which websites would suit their needs and expectations best? The answer to this question is provided by the affinity index, often referred to as AI.

Greater “density” of target internet users

Many marketers are eager to know on which websites they can most easily find internet users with specified socio-demographic traits (such as age, sex, residence or education). They refer to the affinity index for that insight. The indicator shows whether the website’s audience has a greater (AI exceeding 100) or a lesser (AI below 100) share of target group representatives compared to the entire online population.

Tailored website

If the affinity index is more than 100, we are dealing with the so called “over-indexation” of the target group in relation to the whole internet users population. If the value is below 100 – the situation will be quite the reverse, i.e. the target group share among all website’s visitors is smaller than the online population composition would suggest. 

If on a chosen website the affinity index was 200, this would mean that the site is visited by twice as much percent of the target group representatives as in the whole online population. Consequently, you can assume that the chance to get any communication conveyed through that website to the users of the desired socio-demographic profile is doubled.

Most feminine and masculine website?

For instance, among the polish websites concerning culture and entertainment, one well suited to women’s expectations is Over 80 per cent of internet users who enter the website are women (gemiusAudience, October 2014). The affinity index for female users on that website is 159. This means that enjoys visit of over one-and-a-half times more women that they account for in overall online population. In turn, in the same website category, has the largest proportion of male users – 87 per cent (gemiusAudience, October 2014). With the affinity index at 175, the website attracts almost twice the share of men than are present in the whole internet users population.

How to read the affinity index?

The affinity index is actually expressed in percentages. However, for greater clarity and reader-friendliness, it is written without the “%” character. When calculating the affinity index, the values taken into account are expressed in percentages (target group reach in percentage is divided by the reference group reach in percentage), and then the result is multiplied by 100. For example, if the target group reach is 20 per cent, and in the reference group it accounts for 10 per cent, the affinity index in this case at hand will be 200.


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