My goal is to pull in purchase transaction count and transaction revenue from a client, segmented by Google Ads campaign ID. My current query looks like the following:
{
"propertyId": "*********",
"query": {
"dateRanges": [
{
"startDate": "2022-09-30",
"endDate": "2022-10-06"
}
],
"dimensions": [
{
"name": "googleAdsCampaignId"
},
{
"name": "googleAdsCampaignName"
}
],
"metrics": [
{
"name": "advertiserAdClicks"
},
{
"name": "advertiserAdCost"
},
{
"name": "transactions"
},
{
"name": "purchaseRevenue"
}
],
"dimensionFilter": {
"andGroup": {
"expressions": [
{
"filter": {
"fieldName": "googleAdsCustomerId",
"stringFilter": {
"matchType": "EXACT",
"value": "*********",
"caseSesnsitive": false
}
}
}
]
}
}
}
}
What I expect when querying the 'transactions' dimension is, as the API schema describes, "The count of transaction events with purchase revenue. Transaction events are in_app_purchase, ecommerce_purchase, purchase, app_store_subscription_renew, app_store_subscription_convert, and refund."
The response from my query comes back with these numbers, for an example campaign:
{
"dimensionValues": [
{
"value": "***********",
"oneValue": "value"
},
{
"value": "Example Campaign",
"oneValue": "value"
}
],
"metricValues": [
{
"value": "2482480",
"oneValue": "value"
},
{
"value": "6492393600000",
"oneValue": "value"
},
{
"value": "331",
"oneValue": "value"
},
{
"value": "31374.205645000002",
"oneValue": "value"
}
]
}
However, if, in the GA4 dashboard, I attempt to view a report of purchase conversions by campaign over the same date range, this is what is displayed for the 'example campaign':
6 Example Campaign 239.47 31,981.63
Where 239.47 is the number of transactions, and 31,981.63 is the event value (transaction revenue). Notably, the transactions are off by over 25%. The revenue/event value is similar but also off by a slight amount. This is consistent for all campaigns under the client, with the API response being significantly (but by varying percentages) higher. The dashboard value is always lower. These numbers don't change if the report is run on different dates.
Additionally, I suspected that there may be some additional event being tracked under the transactions api field that was not displaying in the dashboard, so I also tried adding this filter to my query:
{
"filter": {
"fieldName": "eventName",
"stringFilter": {
"matchType": "EXACT",
"value": "purchase",
"caseSesnsitive": false
}
}
}
the transactions field still came back as 331.
What I want to figure out is if I'm querying the wrong field, the frontend is under reporting data, or the API is over reporting data. I found that I was not able to post on the official GA4 Issue tracker so I've come here.
Someone better versed in GA4 at my company explained that the issue here had to do with dimension scopes. The transactions field is session scoped, but the dimensions I was pulling in were event scoped. This means that the numbers being output were basically meaningless. As a matter of fact through the dashboard, it won't let you create a free-form explore report using the combination of fields that I did in my query, explaining that the metrics are incompatible. It appears to just be a bug that the API would allow that to happen.
As an alternative, I'm now pulling the conversions field, with a filter on eventName as listed above, including only purchase events.