The rule every chart follows
A chart that uses a metric must also include its data type’s required dimension. Otherwise Looker Studio shows the connector’s error instead of the chart. The required dimension and the exact message per data type:
The connector checks the fields in the chart before it requests any data. Adding the dimension to the chart is the whole fix. Charts made of dimensions only, such as a list of prompts, are not checked.
Brands
A Brands row describes one brand: how often the AI answers in the row’s grouping mention it and how early it appears in them. Looker Studio shows these fields for a Brands data source:
How the connector shapes the values:
- Day is Looker’s Date type. The connector sends each day as a calendar date without a time.
- Mention Rate reaches Looker as a fraction of 1. The connector divides the API’s 0 to 100 value by 100 because Looker’s Percent type expects a ratio. Looker then formats it as a percentage.
- Average Position has no value (null) when Surfer has no position for the brand in that row. It is never zero.
- Mention Rate and Visibility Score fall back to zero when the API returns no value, so a missing rate or score reads
0, not null. - The three metrics are not re-aggregated. Their aggregation reads Auto in the data source and cannot be changed. Each value is the one Surfer computed for the exact dimensions in the chart.
- Add or remove a dimension and the connector asks Surfer for the new grouping. Looker does not add up or average the rows it already has.
Sources
A Sources row describes one page the AI answers cited. It shows how often the answers in the row’s grouping cited it, and which brands Surfer found on the page itself. Looker Studio shows these fields for a Sources data source:
How the connector shapes the values:
- Brand Mentioned and Mentioned Brands describe the page, not the row. They repeat on every row of the same URL, whatever the other dimensions are.
- Both come from the latest completed crawl of the page at or before the chart’s end date, even when that crawl predates the start date.
- Brand Mentioned has no value (null) when no completed crawl exists by the chart’s end date, or when that crawl found no brands on the page.
- Mentioned Brands is one text value with the brands separated by a comma and a space, for example
Surfer, Ahrefs. It has no value in the same two cases. - Times Shown falls back to zero when the API returns no value. Its aggregation is Sum, so Looker adds it up wherever it combines rows.
- A page appears only if it has at least three citations across the chart’s full date range.
- The threshold applies regardless of how the chart’s dimensions group the results.
- When the chart includes Topic, only citations from prompts with a topic count toward the threshold.
Combine dimensions
Any dimensions of one data type can share a chart. A Brands field and a Sources field cannot, because a data source holds one data type.- Within a data type, add as many of its dimensions as the chart needs. Surfer groups the answers by those dimensions, always including the required dimension, and computes the metrics for that grouping. Brand Mentioned and Mentioned Brands describe each URL and never change the grouping.
- Adding Topic narrows the answers to prompts that have a topic. Mention Rate, Visibility Score, and Times Shown can therefore change when it joins a chart.
- To chart Brands and Sources together, add one data source of each type to the report and blend them. Blending is Looker Studio’s own feature for charts built on several data sources. The two data types share Day, Model Family, Prompt, and Topic by name.