Model Google Trends

With this section, we may discuss the actual relevant record background as well as walk via a simple instance. Our record model is actually implemented within R and also the code might be found within the Appendix. The example is dependant on Ford's month-to-month sales through January 2004 in order to August 08 as documented by Auto News. Google Developments data for that category Automotive/Vehicle Brands/Ford can be used for the actual query catalog data.

Denote Kia sales within the t-th 30 days as fyt: capital t = 1; two; ¢ ¢ ¢; T g and also the Google Developments index within the k-th week from the t-th 30 days as fx(tk): capital t = 1; two; ¢ ¢ ¢; Capital t; k = 1; ¢ ¢ ¢; 4g. The ¯rst part of our analysis would be to plot the information to be able to look with regard to seasonality as well as structural developments. Figure 1. 2 exhibits a decreasing trend as well as strong seasonality within both Kia Sales and also the Ford Issue index.

We begin with a easy baseline predicting model: product sales this 30 days are forecasted using product sales last 30 days and 12 several weeks ago.
The adjustable et is definitely an error phrase. This kind of model is famous in the actual literature like a seasonal autoregressive model or perhaps a seasonal AR design.

We following add the actual query catalog for `Ford' throughout the ¯rst week of every month for this model. Denoting this particular variable through x(1)t, we now have


The minimum squares estimates with this model tend to be shown within equation (1. 3). The good coe±cient about the Google Developments variable indicates how the search quantity index is actually positively related to Ford Product sales sales.

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