Privacy Policy

What we collect

Your account

Your email address and, if you set one, your password (stored only as a one-way hash by Supabase Auth), plus when you signed up and last signed in.

Timed tests

For each sitting: the answer you gave to every question, the questions you marked, the time spent on each question, every answer you picked in order (so we can show whether changing answers helped you), start and finish times and your score.

Drills and unlimited PAT practice

Which question you answered, whether it was right and how long it took.

Official DAT scores

Only if you choose to enter them, with your test date. We use them to check how accurate our estimates are.

Messages and problem reports

The name, email address and message you send through the contact form or a question's “Report a problem” link.

Sign-in protection

When you create an account or ask for a sign-in link we record a keyed hash of your IP address and the time, to stop abuse. No raw IP address is stored, and these records are deleted after about a day.

Content-access monitoring

Which tests, drills and reviews you open and when, with a keyed hash of your IP address (never the address itself), kept for 30 days. It slows down opening more than 5 different tests in an hour or 30 in a day and flags an account used from many networks in one day, to stop bulk copying and account sharing. Staff can see those flags next to your email address.

Class access codes

If you signed up with a class code before September 2026 we recorded which code was used and a one-way hash of your email address, so each student uses one seat. The code itself is stored only as a hash.

Error reports

Technical reports when a page fails (for example the page and the error message). They do not include your answers.

Visit statistics

Umami analytics, hosted on our own server: pages viewed, referring site, browser, device type and country, plus named steps such as starting the free sample or submitting a test. Those steps carry no email, answers or scores. It sets no cookies, does not store your IP address and is only read in aggregate.

Stored only in your browser

Some things stay in your browser's local storage and are not sent to us until you submit a test or an answer:

• a test in progress, so a refresh does not lose your work
• passage and question highlights
• your study plan and test date
• unlimited PAT answers waiting to be saved when you are offline

Signing in uses a session cookie from Supabase Auth. We use no advertising or tracking cookies.

How we use it

• To run your tests, show your results, explanations, score estimates and progress, and build drills from questions you missed.
• To improve the questions and scoring: first attempts are used to measure each question's difficulty, and once at least 20 first attempts exist, other students who have finished that test see what share of students chose each answer. These figures are anonymous and never show who answered.
• To support your class: DAT600 staff can see enrolled students' email addresses and practice results.
• To answer your messages and to keep the site secure.

We do not sell your data, share it with advertisers or show ads.

Who processes it

• Supabase - database and sign-in, hosted in the United States (US East).
• Vercel - hosts the website and handles each page request, which includes your IP address.

How long we keep it, and deleting it

Your account and practice records are kept while your account exists. You can delete your account yourself at any time while signed in: that immediately removes your sign-in, test sittings, drill answers, unlimited PAT answers and official scores. Anonymous percentages already calculated are not recalculated. Copies may remain in the database provider's encrypted backups for a limited time until they are overwritten.

Messages you sent us are not linked to your account and are kept until we have dealt with them; email help@tcgcompany.kr to have them deleted, to get a copy of your data or to correct it.

Children

DAT600 is for people preparing for dental school admission and is not directed to children under 16.