Last updated: August 2026
Site operator
whatstheimpact.com is operated by Jonathan Hershaff as a sole proprietor. Written enquiries go through the contact form.
What is sold here
This site sells written and video interview preparation material, delivered through Teachable, and 1:1 coaching sessions, booked and paid through Stripe. Prices are shown in US dollars and are set for candidates targeting senior roles in US tech. Discount codes are available on the written material for people interviewing outside the US or targeting more junior roles, and can be requested through the contact form. Coaching is not discounted, because availability is the binding constraint on it rather than price.
Courses and digital material
Buying a course gives you a personal, non-transferable licence to read and watch the material. You are welcome to use what you learn however you like, including in your own interviews and your own work. You may not resell, republish, or redistribute the material itself, in whole or in part, and access is for one person rather than a team.
Course material is hosted on Teachable, and access is provided for as long as that product remains available. Content is updated over time as interview formats change; updates are included at no extra cost.
Digital purchases are final
All sales of courses and written material are final. The whole Playbook can be read in a day, so a refund window would not mean much, and I would rather price it fairly than build the cost of returns into it. To make sure you know what you are buying before you buy it, there is a free preview lecture and a module-by-module breakdown on the course page, and I am happy to answer questions first. If any of the material is broken, missing, or inaccessible, tell me through the contact form and I will fix it.
Coaching sessions
Sessions are booked in advance and delivered by video call. You can cancel any time up to the day before your session for a full refund, no explanation needed. I will always try to reschedule instead if you would rather, but my calendar is tight and a replacement slot is not guaranteed.
Availability is genuinely limited, so please get in touch before booking if your timing is tight. If I cannot fit you in, I will say so and refund you rather than take a slot that arrives too late to help.
No guarantee of outcomes
Everything here describes what has worked for me and for people I have coached. Interview outcomes depend on your background, the role, the interviewers, and the market, none of which I control. Nothing on this site is a promise of a job, an offer, or a particular salary.
Not professional advice
Articles on this site discuss statistical and causal inference methods, and sometimes describe results from my own business. They are written for general interest and are not financial, legal, or professional advice for your situation.
Third-party links
This site links to other websites, including Teachable, Stripe, Substack, and social platforms. I am not responsible for their content or their handling of your information.
Content ownership
Articles, figures, and course material on this site are my own work unless credited otherwise. Papers, packages, and results by other researchers are cited where discussed. You are welcome to quote and link to posts with attribution.
Privacy
How your information is handled is described in the privacy policy.