I assume you have an external table to store quality assessment scores with a structure like this:
Employee ID - Date of Assessment - Score
What I would do is:
Create a math column to determine the numerical value of the week. It can look like this:
YEAR(D)*100+WEEKNUM(D) with D being the date of assessment.
Create a query column, pointing at the same table, filter by employee ID is this row > employee ID and weeknum equals to this row > week num.
Create a rollup column to get the average number from that relation.
Add a rowID column if you haven’t.
Create a single value column to get the first rowID from the query column.
Go back to your Users table. Add a chart based on the relation from the Users table to the Assessment table, filter the rows to show by rowID equals the single value above (act as a unique function), and show the average number.
You might want to add a few steps to determine the start and end dates of the week to show as labels on the X axis.
You can move the logic to the Employees table, and show the chart in each employee’s details screen. This is assuming you are storing quality assessment scores for employees.