Real-user metrics are aggregated across many different website visitors using different devices. In contrast, to run a lab test you need to select a single test device. That's the case both when testing locally in Chrome DevTools and when using a dedicated performance tool.
Discrepancies between lab and field data are incredibly common. This can be confusing: what data should you believe, and what are the best device and network settings to use when running tests?
The device configuration you should use depends on what your goals are. This guide explores different options and explains their pros and cons.