OCDS and open contracting data: a practical guide

Public procurement generates a record of who buys what, from whom and for how much. In many countries that record is published, but in forty different layouts that no program can read together. The Open Contracting Data Standard, or OCDS, is a shared format that fixes this. Learning to use it turns a mass of tender notices into a dataset you can search, count and compare.

What the standard defines

OCDS describes a contracting process from planning through tender, award, contract and implementation, and it defines the fields used to record each stage. The standard's documentation calls the release schema the authoritative definition of the fields and their structure. The version currently documented is 1.1.5. Required fields are marked in the schema, and the standard is published with a JSON schema plus a CSV version, so you can check whether a file conforms.

The most important idea in OCDS is that data is published in releases and records. A release is JSON data published each time something changes in a contracting process, such as a new notice or an award. Releases follow the release schema and cannot be changed after publication. Together, the releases for one process form its change history.

A record is JSON that indexes all releases for a single contracting process. Each new release is added to the index, so the record updates even though releases do not. A record includes a compiled release, which has the same structure as a release and shows the latest value of each field, and a versioned release, which holds the history of each field and shows how it changed. Every release carries an OCID, the open contracting identifier, that tells you which process it belongs to.

For analysis this gives you two choices. If you want the current state of every tender, read compiled releases. If you want to know how a tender changed, for instance how its closing date moved or how its estimated value was revised, read the versioned release or the sequence of releases.

Where to download Latin American data

The Open Contracting Partnership runs a Data Registry where publishers list their datasets. Three Latin American examples show how different the situation can be, even within one standard.

• Ecuador. The national procurement service, SERCOP, publishes data on the pre-contractual and contractual phases from three systems, covering January 2015 to November 2026. Formats are JSON, Excel and CSV, updated daily at the source and retrieved monthly by the registry. The licence is Creative Commons Attribution 3.0 Ecuador. The all-time JSON file is about 1.1 GB.
• Colombia. The registry's copy of the data from Colombia Compra Eficiente runs from January 2011 to April 2022 and is marked as no longer updated by the publisher. The licence is the Open Data Commons Public Domain Dedication and Licence. The page notes that all public bodies, including state-owned enterprises using public funds, must use SECOP for public contracts, with some exclusions.
• Chile. ChileCompra publishes through an API in real time. The registry copy covers January 2022 to May 2026 and is refreshed every six months. The API covers tenders, direct negotiation and framework agreements, and it does not include the quick-purchase procedure. The licence is CC0.

The point of this list is that you cannot assume freshness. A dataset can be complete for one decade and stale for the next. Always read the registry page for the date range, the update frequency and the licence before you build anything on top of it.

Latin America as a whole has a long record of open contracting reform. The Open Contracting Partnership's regional page names Chile, Colombia, Ecuador, Mexico and Paraguay among the places where digital transformation work has delivered results, and notes that more than 50 countries and cities, from Argentina to Mexico, are pursuing reforms.

A workflow you can run in an afternoon

Pick one publisher and one year. Download the CSV or the JSON lines file. Load it into a notebook or a spreadsheet tool that can handle large tables. Flatten the nested fields you care about: buyer name, tender title, procurement method, estimated value, award date, supplier name and awarded value. Keep the OCID in every table, because it is the key that joins everything else.

Then ask a simple question and let the data answer. Which buyers in your sector spent most last year? How many tenders used open competition and how many used direct awards? How far is the awarded value from the estimate? Which suppliers win repeatedly with the same buyer? For market entry, the last question is the one to ask first, because it shows how contested the market really is.

What to check before you trust the data

Open data helps you find patterns and sources of leads. It does not give audited facts. Several weaknesses recur.

• Gaps. Some processes are missing fields, especially supplier identifiers, values or dates. Count the share of blanks for each field before you rely on it.
• Names. The same company can appear under several spellings or tax identifiers. Clean names with the official registry number when it exists.
• Values. Awarded values may be in different currencies, include or exclude tax, or reflect framework agreements and not actual spending.
• Coverage. Not every purchase goes through the central system. Emergency purchases, state companies and small buys may sit elsewhere.
• Timing. Delayed publication can make the latest weeks look quieter than they were.

Check the licence as well. Creative Commons Attribution means you must credit the source, and CC0 and the public domain dedication do not. If you publish an analysis built on the data, say where it came from and which version you used.

Using it in a bid

The data supports three commercial tasks. First, market sizing: add up the awarded values for your product category by buyer and by year. Second, competitor profiling: see who wins, how often, at what price relative to the estimate and with which buyers. Third, buyer behaviour: learn how long each buyer takes from tender to award, how often tenders are cancelled and how often bidders file complaints. None of this replaces reading the bidding documents. It tells you which tenders deserve that reading.

Guides explain how things generally work. They are not legal, tax or investment advice for a specific project or country. See our editorial policy.