Experimental Evaluation of Scale, and Patterns of Systematic Inconsistencies in Google Trends Data.

Search analytics and trends data is widely used by media, politicians, economists, and scientists in various decision-making processes. The data providers often use sampling when calculating the request results, due to the huge data volume that would need to be processed otherwise. The representativity of such samples is typically assured by the providers. Often, limited or no information about the reliability and validity of the service or the sampling confidence are provided by the services and, as a consequence, the data quality has to be assured by the users themselves, before using it for further analysis.