%% date:: [[2023-04-30]] parent:: [[Measurement]], [[Frontend performance testing]] sibling:: [[Lab data]] opposite:: [[Lab data]] %% # [[Field data]] Field data refers to information gathered in a production environment, and is generally held to be more current and realistic. It is the opposite of [[Lab data]], which is collected in controlled environments. ## Advantages of field data - It's more realistic, and thus more predictive of actual user behavior (or system behavior under real user load). - It covers use cases you might not have thought to explicitly measure in [[Lab data|lab tests]], such as user journeys that vary from the happy path. ## Disadvantages of field data - It requires a tool that is capable of more complex scripting. By contrast, lab data can be gathered by pointing a tool at a URL. - It takes more time and management to set up, execute, and analyze. - It can be more difficult to pinpoint issues because of the large number of variables present in the data. ## In frontend performance testing In [[Frontend performance testing]], field data refers to measurements regarding user experience that are taken from either real users or scripts simulating real users (i.e., [[Browser-based testing|interacting with a browser]] rather than by [[Protocol-based load testing|sending messages on the protocol layer]]). Compared to [[Lab data]], field data is influenced by things like device differences, network slowness, and other browser optimizations users might be employing. [^google] [^google]: Google. *Why lab and field data can be different (and what to do about it).* Retrieved April 30, 2023 from https://web.dev/lab-and-field-data-differences/