I loved the prominent placement of that graph.<p>Makes a strong, unambiguous statement right off the bat as to why I should be interested in this project.  If nothing else, shows me the project&#x27;s goals and priorities are aligned in the right direction.<p>Having said that, I suppose the best approach would be to randomly assign developers to learn a language&#x2F;technology stack they haven&#x27;t used before, then have them learn the technology and implement a project in the language.  Would evaluate difficulty of learning the language, availability of resources, and the strength of the community.<p>If you evaluate performance based on language&#x2F;stack the developers already know, would be difficult to tease apart the correlation between technology stack and developer ability.