Unit Spectrum

`GET /portfolio/unit/{id}/spectrum`

Returns the aggregated OpenAlex research spectrum for one unit.

Parameters

Parameter	Type	Description
`id (path)`	string	Exact group ID, or `0` for the root group.
`apikey`	string	Portfolio API key, if configured; alternatively use `X-API-Key`.
`limit`	integer	Maximum list rows. A positive value enables shared pagination.
`offset`	integer	List rows to skip with `limit`. Defaults to `0`; negative values become `0`.

Authentication, pagination, and error envelopes are described in Portfolio API Basics. Parameters such as json, filter, columns[], full, and aggregate are not supported unless listed here.

Example Request

1	`GET /portfolio/unit/BIO/spectrum?apikey=YOUR_PORTFOLIO_API_KEY`

Example Response

{
  "status": 200,
  "count": 1,
  "data": [
    {
      "_id": "T12345",
      "count": 4,
      "sumScore": 3.2,
      "topic": {
        "id": "T12345",
        "name": "Example Biology Topic",
        "score": 0.8
      },
      "total": 8,
      "avg_score": 0.8,
      "share": 0.5,
      "weight": 0.2
    }
  ]
}

The example uses illustrative values. Optional stored or rendered fields may be omitted. Response count is the number of returned list rows before shared pagination.

Returned Fields

Field	Description
`_id`	OpenAlex topic ID, e.g. `T12345`.
`count`	Number of assigned topic occurrences in matching publications.
`sumScore`	Sum of stored topic scores.
`topic`	First stored OpenAlex topic object for this group, including available ID/name/score/hierarchy metadata.
`total`	Number of matching publications with non-empty assigned OpenAlex topics.
`avg_score`	`sumScore / count`.
`share`	`count / total`.
`weight`	`(count / total) * (sumScore / total)`.

Response Behavior

Matches publication units by exact group ID, without descendants. 0 resolves to the level-0 root ID.

Requires publication type=publication and non-empty openalex.topics. The spectrum helper does not add hide, affiliation, or workflow restrictions. Topics below 5% share are discarded; remaining topics are sorted by weight descending and capped at 25 before shared pagination. Response count is the retained number of topics, not source publications.

When portfolio-spectrum is disabled, or no matching assignments exist, returns a successful empty array. The local data contained no spectrum rows; the non-empty example follows the helper implementation.