The AdSense Management API has calls to generate new and saved reports. They can
contain simple analytics like earnings per day or very complex tables of
click-through rates per custom channel per country. This guide presents a list
of edge cases that should be correctly handled for a robust integration with
the APIs.

## Report structure

Report results are returned as a `ReportResult` object. See
[the report
response reference](https://developers.google.com/adsense/management/reference/rest/v2/ReportResult) for full detials.

## Using chronological dimensions: DATE, WEEK, and MONTH

### Reports can be empty or have gaps

If there was no activity during the time period specified in the request, no
ad requests are generated and the report service won't show rows for those time
periods. This is important if you are, for example, plotting a graph.

Check out the [Filling in
Dates guide](https://developers.google.com/adsense/management/reporting/missing_dates) for more information.

### Requesting MONTH and WEEK dimensions in the same report

This report can have **negative or unexpected** consequences. If a week
belongs to two different months, it will show two rows for the same week, one
for each month.

#### Example

| Dimensions | Metrics | Start date | End date |
|---|---|---|---|
| `WEEK` `MONTH` | `CLICKS` | 2014-04-28 | 2014-05-03 |

##### Returns:

| `MONTH` | `WEEK`\* | `CLICKS` |
|---|---|---|
| 2014-04 | 2014-04-27 | 50 |
| 2014-05 | **2014-04-27** | 43 |

\* first day of the week

##### Solution

Remove `MONTH` from the report.

| `WEEK` | `CLICKS` |
|---|---|
| 2014-04-27 | 93 |

## Collating dimension values

When requesting dimensions like the ones related to, for example,
**platforms** (desktop, high-end mobile devices, etc.), only the platforms
with activity will be shown. If a given day, week, or month has no visits from
high-end mobile devices, it will have no information for that category.

#### Example

| Dimensions | Metrics | Start date | End date |
|---|---|---|---|
| `PLATFORM_TYPE_NAME` `MONTH` | `AD_REQUESTS` | 2014-02-01 | 2014-03-31 |

##### Returns:

| MONTH | PLATFORM_TYPE_NAME | AD_REQUESTS |
|---|---|---|
| 2014-03 | Desktop | 100 |
| 2014-03 | High-end mobile devices | 5 |
| 2014-04 | Desktop | 75 |

##### Solution

When processing the report results, assume a value of zero for any dimension
values that do not appear in the results:

| MONTH | PLATFORM_TYPE_NAME | AD_REQUESTS |
|---|---|---|
| 2014-03 | Desktop | 100 |
| 2014-03 | High-end mobile devices | 5 |
| 2014-04 | Desktop | 75 |
| **2014-04** | **High-end mobile devices** | **0** |

## Combining multiple contiguous reports

Sometimes a report is too large to be generated all at once and it has to be
batched. If your app does this, consider these cases:

- If you're using `WEEK` or `MONTH` dimensions and you're splitting the report in the middle of a week or month, each report will have duplicated entries with different data.
- Make sure all the reports have the same metrics and dimensions, as data might not be combinable using different dimensions.

## Special accounts

Some of your users might have AdSense accounts with attributes that you
don't expect or know about. Make sure to take into account:

- Publishers with thousands of domains or sites
- Publishers with thousands of ad units or custom channels
- Publishers that would like to report on multiple ad clients (AdSense for Search, AdSense for Video, etc.)

## Multiple accounts

Users can have access to more than one AdSense account. An account ID has to
be specified for every call to the API for this reason. A call to
`accounts.list` fetches a list of accounts and an account chooser
dialog should be displayed to the user. It can be bypassed if the number of
fetched accounts is one.

## Time zone changes

AdSense Publishers can change their timezone at any time and this can
produce spikes or dips in the reports. Read the guide about
[Local Time Zone Reporting](https://developers.google.com/adsense/management/timezone) for more
information.