The test can not be conclusive unless all of them worked on same type of projects, programming languages and faced same bugs over the years. It's quite likely

The test can not be conclusive unless all of them worked on same type of projects, programming languages and faced same bugs over the years. It's quite likely the so called rockstar had a prior experience in the problem at hand. It will be good to see the engineers learn an entirely new language and solve an entirely unrelated problem The thing to draw out from the study is hire the right fit. There is nothing called rock star engineer. You rockstar engineer is the best fit for your job, tech stack and challenges in your business.