Bill Gates and Mark Zuckerberg are backing it with hundreds of millions of dollars. States from Florida to Vermont have adopted supportive laws and policies. And school districts across the country are embracing this emerging education trend. But as “personalized learning” takes root, it’s also coming under greater scrutiny. Leading researchers say their work does not support the most enthusiastic claims being made by personalized-learning supporters. Education experts are raising questions about implications for teaching and learning. Tech-industry critics are sounding alarms about Silicon Valley’s growing influence over public schools. And a small but vocal coalition of parents and activists …