Google Trends is a great source for insight, but the tool can be a bit limiting. For instance, it is only possible to download daily search data three months at a time. Google Trends will give you weekly data for up to a year at a time, and after that only monthly data. Since the data is provided in an index format, we need to adjust the independent indexes. So how can we merge the quarterly time series into a yearly time series with daily data?
The three graphs show the problem of merging quarterly data directly. By using the weekly data as a benchmark we can create an accurate index with daily data.
Step 1
Download the data in 90-day increments. In this example I assume that we want a whole year worth of daily data, that means four csv files to merge.- Report (1).csv: January - March 2012
- Report (2).csv: April - June 2012
- Report (3).csv: July - September 2012
- Report (4).csv: October - December 2012
Step 2
Download the weekly data for the same year.- Report (5).csv: January - December 2012
Step 3
Merge the daily data files into one Excel spreadsheet. Leave a gap in between each quarter so you remember where the adjustment must be made.Step 4
This is where we need to adjust the indexes based on the weekly data file we downloaded. We will do this based on the weekly time series data for the whole year we also downloaded. At the start of each quarter, write the corresponding index value from the weekly data. Then calculate the percentage change between the days and add that to the new index value. Repeat for each quarter and you have created a new yearly index with daily data.
