Susan Preator found her entrepreneurial calling at an unusual time: post-retirement.

Preator, now president and chief executive officer of Imagine Learning, worked for more than a decade at the Waterford Institute, building and directing the team that created the Waterford Early Reading Program, which has been used to teach millions of children in U.S. public schools. She retired from the institute in 2000.

But in 2002, Preator and several of her former associates realized there was a new opportunity that fit their skill set and had international demand: teaching English to the students of the world.

Preator and her associates formed Imagine Learning to fill this need. The initial six-person team had three programmers, an instructional designer, a sales manager and Preator, whose charge was assembling the right team and securing resources and funding.

With everything in place, the team created its flagship product, a language and literacy software program that gives students one-on-one instruction in English through hundreds of interactive lessons. The student experience features art, music and other engaging elements supported by rigorous research into effective teaching and learning practices.

Imagine Learning sells the product to school districts with a per-student license, renewable each year. This business model automatically motivates the company to keep its products and services fresh, effective and relevant.

The proof that Imagine Learning, now in a new facility with around 100 employees, is succeeding in this goal is its impressive 92 percent renewal rate among the more than 2,000 schools that use its products.