**Estimated Impressions**

How many people search for the term? For this Adthena uses Google Keyword Planner Monthly Volume estimate to provide a consistent starting point for all competitors. A competitor who appears every time Adthena searches for that term will have 100% Impression Share.

**Estimated CTR**

Adthena uses a complex machine learning model to estimate nightly both CTR (click through rate) and CPC (cost per click) for every single search term, for every competitor in every position we have seen them appear in that day.

This model is constantly learning from the 5 terabytes of new data that Adthena is collecting daily, but essentially it uses the following inputs:

- What is the country?
- What is the device? (there is a separate model for mobile)
- Who is the competitor? (their size, overlap, appearance frequency)
- What is the search term? Is it brand or generic?
- How many advertisers compete on this search term?
- Is the most frequent position above the fold (top of the page or bottom)?
- What times of the day and days of the week does the advertiser generally appear on this term?
- Are there other items on the page (site links, other extensions, knowledge boxes, image search, PLAs, comparison boxes) that could draw clicks away from this advert?

**Estimated Clicks**

Let’s say a search term gets 1,000 searches per month and a competitor’s advert appears on the term 60% of the time, so they generate 600 impressions. They always appear in position 2 with a CTR estimated at 5% which equates to 30 clicks per month.

The following week the competitor is seen 80% of the time fluctuating (70:30) between position 2 and position 3. The model has re-estimated the CTR for position 2 to 6% and for position 3 estimated 3.5%.

Example:

1000 searches / (30 * 7 days) * 80% frequency = 187 impressions that week

(187 impressions x 70% p2 frequency x 6% CTR) + (187 x 30% x 3.5%) = 10 clicks

Estimating Clicks gets more complicated when you include additional competitors on the same search term and additional search terms (that have different search volumes and sets of competitors).

**Estimated CPC**

The model estimates the CPC for each competitor in each position in a very similar way to estimating CTR. Is it a brand term? Is it the brand owner? How many different competitors are appearing? etc. (see above for full list).

**Estimated Share of Spend**

A competitor’s spend is estimated by multiplying their estimated clicks for each search term by their estimated CPC for that search term. The total spend for all competitors can then be calculated and each competitors spend divided by the total is their Share of (the total) Spend.

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