---
title: "TFP panel - Penn World Table productivity series"
method: GET
path: "/api/v1/research/pwt/tfp-panel"
tags: ["Research"]
---

# TFP panel - Penn World Table productivity series

`GET /api/v1/research/pwt/tfp-panel`

Specialised view on Penn World Table Total Factor Productivity series. Returns a country-year panel restricted to productivity variables - by default the four headline TFP series: `ctfp` (TFP level at current PPPs, USA=1), `cwtfp` (welfare-relevant TFP level), `rtfpna` (TFP at constant national prices), `rwtfpna` (welfare-relevant TFP at constant national prices). Slice by country list and/or year list. Year list supports single years (`2015,2020,2023`) and ranges (`2010-2023`). Welfare-relevant TFP (`cwtfp`, `rwtfpna`) is a PWT-unique metric - not published by IMF, OECD, or the World Bank. Published under CC BY 4.0 with attribution to Penn World Table (Feenstra, Inklaar & Timmer, University of Groningen).

## Query parameters

- `countries` string, nullable — Comma-separated ISO 3166-1 alpha-3 country codes (max 50). Omit for all countries.
- `years` string, nullable — Comma-separated year list. Supports single years (`2015,2020`) and ranges (`2010-2023`). Omit for the full panel.
- `variables` string, nullable — Comma-separated TFP variable names. Defaults to `ctfp,cwtfp,rtfpna,rwtfpna`.
- `version` string, nullable — Release selector. `pwt1100` (default) or `pwt1001` (legacy).

## Response `200`

Country-year TFP panel with productivity variables.

- EnvelopePwtTfpPanelPayload
  - `data` PwtTfpPanelPayload, required — Specialized TFP panel - productivity series across the requested slice.
    - `version` string, required — Release identifier.
    - `variables` string[], required — Productivity variables returned. Defaults to `ctfp`, `cwtfp`, `rtfpna`, `rwtfpna` (the four headline PWT TFP series).
    - `observations` PwtObservation[], required — Country-year rows with productivity variables, sorted by countrycode then year.
      - `year` integer, required — Observation year.
      - `countrycode` string, nullable — ISO 3166-1 alpha-3 country code.
      - `country` string, nullable — Country name as published.
      - `currency_unit` string, nullable — National currency unit.
    - `count` integer, required — Number of rows returned.
    - `attribution` string, required — CC BY 4.0 attribution.
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

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