How valid tests are actually built and validated.
An open textbook on measurement, reliability, validity and experimental design. Read it and you will be able to tell a serious psychometric instrument from a quiz written for clicks.
Thousands of hours of coding lessons and certifications.
Interactive course · BSD / open
The best introduction to computer science, free to audit.
Video course · Creative Commons
Maths, science and economics from basics to advanced.
Course platform · Free tier — no card required
Real MIT course materials, openly published.
Course materials · Creative Commons
Free courses, frequency lists and spaced repetition.
App + decks · AGPL / open source
Measurable typing improvement in minutes a day.
Web app · GPL / open source
Shrink video files without visible quality loss.
Desktop app · GPL / open source
Editable ad, story and thumbnail templates.
Editable templates · Free tier — no card required
NDAs, contractor agreements and SAFEs, openly licensed.
DOCX / PDF · Creative Commons
