What counts as an OER?

An open educational resource is any teaching or learning material released under a licence that lets anyone use, adapt and redistribute it — usually at no cost. The category is deliberately broad. Textbooks, lecture slides, lesson plans, videos, quizzes, simulations, entire courses: if it carries an open licence and serves an educational purpose, it qualifies. The term was formally coined at a UNESCO forum in 2002, and the concept has grown steadily since, pushed along by the Creative Commons licensing framework that gave educators a practical, legally sound way to share work.

The licence is what separates an OER from a freely viewable resource. A YouTube video you can watch but not legally download, edit or embed in a course is not an OER. A textbook chapter released under a Creative Commons Attribution licence — meaning you can copy it, modify it and redistribute the result as long as you credit the author — is. The distinction matters because "free to access right now" and "free to build on forever" are very different things.

Creative Commons licences come in several flavours, and they affect what you can do with a resource. The most permissive is CC BY: attribute the author, do what you like. Add ShareAlike (CC BY-SA) and any adapted version must carry the same licence. Add NonCommercial (CC BY-NC) and commercial use is off the table. Add NoDerivatives (CC BY-ND) and you can share it unchanged but not remix it — some argue that last one barely counts as open, since adaptation is core to how educators actually work. When evaluating any OER, the licence is the first thing worth checking.

The five Rs

Educators often describe OER through what are called the five Rs: Retain, Reuse, Revise, Remix and Redistribute. The framework was developed by open education researcher David Wiley and it does useful work — it shifts the question from "is this free?" to "what can I actually do with it?" Retaining means you can keep a copy; reusing means you can use it in your teaching unchanged; revising means you can adapt it; remixing means you can combine it with other materials; redistributing means you can share your version with others. A resource that scores on all five is genuinely open. One that scores on only one or two may still be useful but it is not fully open.

This framework helps explain why open licensing is not just an idealistic gesture. When a lecturer can take an openly licensed chemistry textbook, update a chapter to reflect newer research, add local examples, swap out a confusing diagram and redistribute the revised version to students at no cost, the educational gain is concrete. That kind of iterative improvement is impossible under conventional copyright.

Where to find them

Several platforms have become reliable starting points. The Directory of Open Access Journals is geared toward research, but the wider open ecosystem overlaps heavily with OER. For educational materials specifically, a few hubs stand out.

OER Commons is one of the largest curated libraries, spanning K-12 through higher education, with filtering by licence, subject, level and material type. MERLOT (Multimedia Educational Resource for Learning and Online Teaching) has been collecting and peer-reviewing open materials since the late 1990s, with particular depth in higher education. OpenStax, a nonprofit based at Rice University, produces peer-reviewed open textbooks in high-enrolment subjects — introductory science, economics, statistics, history — that are professionally typeset and freely downloadable in multiple formats. Millions of students now use OpenStax titles.

Repositories like Zenodo also hold openly licensed educational materials alongside research data and publications, and a growing number of universities maintain their own OER libraries. For open textbooks specifically, the BC Campus OpenEd repository, developed in British Columbia, has become an important resource for post-secondary education, particularly in Canada.

Search engines can help too. Google's advanced search allows filtering by licence type; Creative Commons operates its own search tool that pulls from openly licensed content across multiple platforms. Neither is perfect, but both beat hoping that whatever ranks first happens to be reusable.

Why it matters beyond cost

The cost argument for OER is real and well documented: commercial textbook prices have risen sharply over decades, and research consistently links high material costs to students delaying purchase, sharing copies, or going without — all of which affect learning outcomes. OER removes that barrier entirely. But the deeper benefit lies beyond price: because open materials can be revised and remixed, educators can adapt them to their own students, local context and current research, then share the improved versions so that resources get better over time instead of staying locked in a fixed edition.