The Big Engine is about a young boy who discovers an abandoned train and uses his imagination to embark on an epic adventure. As he goes on more daring and exciting trips, he learns the importance of teamwork and perseverance.

The Shadow-Gods is a fantasy novel that follows a young woman's quest to stop a group of dark deities from breaking free and wreaking havoc on the world. She must learn to harness her own inner power and unite with unlikely allies to defeat the Shadow-Gods.

Critical difference, also known as minimal important difference or clinically meaningful difference, refers to the smallest measurable change in a clinical outcome that would be considered significant by patients, clinicians, or researchers. It is used to determine whether an observed change in a patient's condition is due to a treatment or just natural variation.