It's good and useful for independent researchers to collect their own data and analyse it. That's a check on the data collection methods. It's also useful for

It's good and useful for independent researchers to collect their own data and analyse it. That's a check on the data collection methods. It's also useful for others to check the analysis of trusted data. If they do it with their own methods and get a different result, then it's time to actually compare the methods. It's a good thing for the original researchers to release their code too. But looking for bugs in the code is no substitute for doing independent analysis and independent data collection. It's an important supplement, but it isn't enough.