Effective Date: March 24, 2026 | Last Updated: August 29, 2026

Thank you for using STEM Critical Thinking (stemcriticalthinking.com), operated by STEM Critical Thinking LLC ("we," "us," or "our"). This Privacy Policy explains how we collect, use, disclose, and protect your personal information when you use our platform and services. By using our services, you agree to the practices described in this policy.

1. Information We Collect

We collect the following categories of personal information:

- Account Information: Full name, email address, display name, and hashed password when you register.

- Essay Submissions: The essay text you write and submit through our platform, including timed and practice mode submissions.

- Quiz Responses: Your answers to STEM Critical Thinking test questions.

- AI Feedback and Scores: Essay scores and feedback generated by our AI-powered grading system and stored in our database.

- Payment Information: Payment transaction IDs and subscription dates. We do not store your credit card number — all payment processing is handled securely by Stripe, Inc.

- Parent/Guardian Contact Information: If you ask us to send a payment link to a parent or guardian, we collect and store the email address you provide for them, along with the status of that invitation, solely to deliver the payment link and record whether it was paid. If you provide someone else's email address, you confirm you have their permission to do so.

- Referral Information: If you invite someone to the platform, we store the invitee's email address (and optional name) you provide, your referral link and its click count, and the status and rewards associated with each referral.

- Email Change History: If you change your account email address, we retain a record of the previous address so we can reconcile your account against earlier payment and support records.

- Login and Activity Data: Timestamps of logins, IP addresses, browser type, and pages visited.

- Communications: Feedback, support requests, and review submissions you submit through the platform.

- Automatically Collected Data: Via Google Analytics (gtag.js), we collect anonymized data about how users interact with our website, including pages visited, session duration, and device information.

2. How We Use Your Information

We use the information we collect to:

- Create and manage your account and authenticate your identity.

- Evaluate and grade your essays using our AI-powered system (powered by Google Gemini, with OpenAI and Anthropic used as backup providers if the primary service is unavailable).

- Deliver AI-generated essay feedback and scores to your registered email address via PDF.

- Process payments and manage your subscription through Stripe.

- Send transactional emails including registration confirmation, payment receipts, password resets, and essay results (via Amazon Web Services Simple Email Service).

- Analyze platform usage and improve our services.

- Display your progress, scores, and ranking on leaderboards (using your display name, not your real name).

- Publish reviews you choose to submit on our public Reviews page, shown together with your display name, your star rating, and the date. Reviews are visible to anyone, including visitors who are not logged in. Do not include personal information in a review that you do not want to be public. To have a published review removed, contact us.

- Respond to your feedback and support requests.

- Comply with legal obligations.

3. Third-Party Services

We work with the following third-party service providers who may process your data on our behalf:

- Stripe, Inc. (stripe.com): Payment processing. Stripe's Privacy Policy governs their handling of your payment data.

- Google LLC: We use AI services for essay evaluation, Google Analytics for website analytics, and Google reCAPTCHA v2 to prevent bot abuse on login and registration forms. Google's Privacy Policy governs their data practices.

- Amazon Web Services (AWS SES): Transactional email delivery (confirmation emails, receipts, feedback PDFs).

- OpenAI, L.L.C. and Anthropic, PBC: Backup AI essay-grading providers. If our primary grading service (Google) is unavailable, your essay text is sent to one of these providers instead so your essay can still be graded. These providers are used only as a fallback, and only for essay grading.

These providers are required to process your data only as necessary to provide their services to us and in accordance with applicable law. We do not sell or rent your personal information to any third party.

4. Cookies and Tracking Technologies

We use session cookies to keep you logged in during your visit. We also use Google Analytics, which places analytics cookies on your device to help us understand how users interact with our platform. You may disable cookies in your browser settings; however, doing so may limit your ability to use certain features of the platform.

5. Data Retention

We retain your account data, essay submissions, quiz responses, and AI-generated scores for as long as your account is active or as needed to provide our services. If you request account deletion, we will delete or anonymize your personal data within 30 days, except where retention is required by law (e.g., payment records, which we retain for up to 7 years for accounting purposes).

6. Data Security

We implement technical and organizational measures to protect your data, including:

- Passwords are stored using industry-standard one-way hashing.

- All data is transmitted over HTTPS/TLS encryption.

- Essay feedback PDFs are stored in a secure server-side directory not publicly accessible.

- Access to personal data is limited to authorized personnel on a need-to-know basis.

Despite these measures, no system is completely secure. We cannot guarantee absolute security of your data.

7. Children's Privacy (COPPA)

Our platform is designed for students preparing for competitive STEM admissions exams, which typically includes students in 8th grade (ages 13 and older). We do not knowingly collect personal information from children under 13 years of age without verifiable parental consent. If you are under 13, you must have a parent or legal guardian create and manage your account. If we learn that we have inadvertently collected personal information from a child under 13 without parental consent, we will delete that information promptly. Parents or guardians may contact us to review, correct, or delete their child's data.

8. Your Rights and Choices

- Account and Data Access: You may log in to view your account information, essay submissions, and scores at any time.

- Account Deletion: To request deletion of your account and associated personal data, contact us with the subject 'Account Deletion Request.' We will process requests within 30 days.

- Email Opt-Out: You may opt out of non-transactional emails by contacting us. You cannot opt out of transactional emails (e.g., payment receipts, password resets) while your account is active.

- Data Correction: Contact us to correct inaccurate personal information in your account.

9. Virginia Consumer Data Protection Act (VCDPA)

If you are a Virginia resident, you have the following rights under the VCDPA: the right to access your personal data, the right to correct inaccuracies, the right to delete personal data provided by or obtained about you, the right to data portability, and the right to opt out of the processing of personal data for targeted advertising. To exercise any of these rights, contact us. We will respond within 45 days as required by law.

10. California Privacy Rights (CCPA/CPRA)

If you are a California resident, the California Consumer Privacy Act (CCPA) grants you additional rights, including the right to know what personal information we collect and how we use it, the right to request deletion of your personal information, and the right to opt out of the sale of personal information. We do not sell personal information. To exercise your California privacy rights, contact us.

11. Changes to This Privacy Policy

We may update this Privacy Policy from time to time to reflect changes in our practices or applicable law. We will notify users of material changes by updating the 'Last Updated' date at the top of this page. Your continued use of the platform after changes are posted constitutes your acceptance of the updated policy.

12. Contact Us

If you have questions, concerns, or requests regarding this Privacy Policy or your personal data, please use our Contact Us form.