What a supplementary application is. A supplementary application is any part of your admission file beyond your grades — a written statement, a list of activities, an interview, a portfolio, or a reference. Different programs ask for different things, but they all share one purpose: to see evidence of who you are and what you've actually done, not just your marks. The Ontario tools you'll likely use. In Ontario, the two you'll hear about most are the OUAC (which covers applications and supports some supplementary components) and the Waterloo AIF. Waterloo's AIF is a structured form asking for your activities, positions, contest results, and short written responses. McMaster Health Sciences uses a written submission plus an interview (CASPer-style). Queen's Commerce and Ivey ask for activity lists with structured written answers. Each has its own format — read exactly what each wants. Show evidence, not adjectives. The most common mistake is telling — 'I'm passionate about engineering' — instead of showing, 'I led a six-person robotics team that placed top ten at VEX provincials.' Admissions teams read hundreds of applications; concrete, specific evidence is what they can actually assess. Every claim should be backed by a concrete role, timeframe, and outcome. Quality and depth over a long list. A spreadsheet of thirty shallow activities is weaker than three activities where you had real responsibility over several years. Depth signals commitment and growing leadership. The Extracurriculars explorer and Your Extracurriculars dashboard help you structure exactly this — role, hours, commitment level, and progression. Start the supplementary early. Because supplementary deadlines (usually January–February) can be earlier than you expect, and because strong answers are a product of reflection more than writing skill, start gathering your activities, contest results, and best stories in the fall — well before the main application deadline. Then the shorter writing task is mostly revision, not first draft.