Synthesized answer
The author provides evidence in the form of a 4-step framework for solving system design interview questions and detailed solutions to 16 real system design interview questions [1]. These solutions are described as being from an insider's perspective on what interviewers are looking for [1].
The passages do not explicitly detail what specific evidence supports this 4-step framework or the solutions provided. They only state that these elements are included in the book as the author's evidence and insights.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: System Design Interview - an Insider's Guide by Alex Xu, Sahn Lam Description: An insider's take on what interviewers are really looking for and why including: a 4-step framework for solving any system design interview question and 16 real system design interview questions with detailed solutions.