The period of the report refers to the amount of aggregation that is being visualized in the chart. This feature aggregates the daily reports into the desired aggregations, averaging prices and adding volumes.
When creating a new report, the default is weekly aggregation. However, through Price Alerts and the links available in the Stories section, reports can have any aggregation available in the system. To change the level of aggregation that is made available through the report, use the 'Period' dropdown in the shaded view menu available under the filters.
When you change the period between days, weeks and months, the system will automatically maintain a similar timeframe between the different periods available.
For example, if you are looking at a daily report with 60 days in the chart and want to change it to weeks, the system will automatically calculate that 60 days is equal to about 9 weeks, which will be the number of weeks presented in the new report. Likewise, if the report is changed to months the system will by default offer a report for two months, as it will be the most representative of a 60-day period.
In the yearly reports, the default is always six years, regardless of the report that precedes it.
Weekly, monthly, and yearly values are all calculated from daily data and include all points reported by the source. Monthly and yearly values are calculated from the first date of the period to the last date of the same period. Weekly values are calculated from Monday to Sunday, which can influence the totals compared to how the USDA calculates weeks, which is from Sunday to Saturday.
