Geopath Reach & Frequency (Single Unit)

For many marketing campaigns, volume of impressions is the goal and lots of audience is key. However, it is critical for most marketers to understand the number of unique individuals that saw their message and how many times over the course of the campaign. These metrics are known as reach and frequency.

Reach measures how many different people see an advertisement. It counts each person only once, no matter how many times they see a unit during a specific period, such as a week or month.

Frequency measures the average number of times the target audience will see the advertisement during a specific period, such as a week or month.

Trip Frequency Distribution

As reported by the NHTS, the average number of daily trips per person is approximately 4. For working individuals, commuting trips represent half of their daily trips on weekdays. While commuting trips may seem like the only reason working individuals travel, but in fact, commuting trips account for a small percentage.

Trip frequency is important to understand because as time goes on, the frequency of trips by the same individual over the same roadway behaves in a unique way. Every day there are a few people that are traveling along that roadway for the first time and there are others that may have traveled along that route many times.

Trip frequency distribution for one day. After one day, a little over 10% of persons circulating by a specific media unit see it twice. One or 2% of persons see it three times. The majority see it one time.

Trip frequency distribution for one week. After one week, just under 17% of persons see a media unit 5 times and the same amount see it 6 times.

Impact of Likelihood-to-See Impressions

The process of predicting the likelihood-to-see an out-of-home media unit is important for reach and frequency. As people are exposed to the same location over time, each opportunity is treated as an independent event and the cumulative probability is multiplied against each corresponding frequency distribution group. While the probability of a single event may be low, over many opportunities the likelihood that a person saw the event approaches 1.

In addition to basic reach and frequency, which asks how many people saw the content at least once, there are some campaigns that may want to know the reach of individuals who saw the event at least n times. This is known as effective reach and is calculated in a similar fashion with cumulative probability using a binomial distribution.