Change Over Time Calculation

Change over time calculations compare the current value with a value from a previous period and display the amount of change between them. Rather than showing the original value or the previous value itself, the chart shows how much the value increased or decreased over time.

Change over time calculations are useful when you want to track growth, decline, volatility, or performance trends across time periods. They can help reveal whether a measure is improving, worsening, or remaining stable.

Change Over Time is only available when a date attribute is bound to the Axis (Category) data binding slot. It can also be used when a date attribute is bound to the Legend (Series) data binding slot, although that scenario is less common and typically more complex.

Applying a change over time calculation fundamentally changes how the chart is interpreted. The value axis no longer represents the original measure. Instead, it represents the numeric difference or ratio between the current value and a previous value, depending on the selected configuration.

Understanding Change Over Time Calculation Settings

When you select Change Over Time from the Quick Functions menu, several predefined options are available.

Growth Rate

Growth Rate shows the relative rate of increase or decrease between the current period and the previous period. Unlike a simple numeric difference, growth rate focuses on how much larger or smaller the current value is compared to the earlier value.

From Previous Period

From Previous Period compares each value to the immediately preceding period in the sequence.

For example:

Years are compared to the previous year.
Quarters are compared to the previous quarter.
Months are compared to the previous month.
Weeks are compared to the previous week.

Same Period, YoY

Same Period, YoY stands for year-over-year comparison. It compares each value to the same period in the previous year.

For example, Q2 2026 is compared to Q2 2025.

Same Period, QoQ

Same Period, QoQ stands for quarter-over-quarter comparison. It compares each value to the same period in the previous quarter.

Same Period, MoM

Same Period, MoM stands for month-over-month comparison. It compares each value to the same period in the previous month.

Same Period, WoW

Same Period, WoW stands for week-over-week comparison. It compares each value to the same period in the previous week.

Advanced

The Advanced option provides more control over how the comparison is calculated. It is also shared by related Quick Functions such as Past Value and % Change Over Time.

The Advanced configuration panel includes the following settings:

Period Unit

The Period Unit determines the time interval used for the comparison.

Available options are:

Year
Quarter
Month
Week
Day
Hour
Minute
Second

Period Offset

The Period Offset determines how far backward or forward the comparison should look.

A value of -1 compares the current value to the immediately previous period. For example:

Year with an offset of -1 compares to the previous year.
Quarter with an offset of -1 compares to the previous quarter.
Month with an offset of -1 compares to the previous month.

You can also use larger offsets. For example, an offset of -2 compares to two periods earlier, while an offset of 1compares to the next period.

Calculation Type

The Calculation Type determines how the current value and the previous value are compared.

Value returns the actual value from the previous period.
Ratio returns the ratio between the current value and the previous value.
Difference returns the numeric difference between the current value and the previous value.
Percent Difference returns the percentage change between the current value and the previous value.

The selected calculation type can also affect which Quick Function appears selected in the menu:

If Calculation Type is set to Value, the Quick Function remains under Past Value.
If Calculation Type is set to Ratio or Difference, the Quick Function appears under Change Over Time.
If Calculation Type is set to Percent Difference, the Quick Function appears under % Change Over Time.

Similarly, when the Advanced settings match one of the predefined options, the predefined option appears selected in the Quick Functions menu. For example, if the configuration uses:

Period Unit: Year
Period Offset: -1
Calculation Type: Difference

then the Quick Functions menu displays Same Period, YoY rather than Advanced. The Advanced label typically only appears when the configuration does not match one of the predefined options.

Change Over Time on a Column Chart

In this example, a change over time calculation is applied across the dataset to show year-over-year sales changes by quarter.

Create a column chart and bind Sales Amount to the Values data binding slot.
Bind Date (Year) and Date (Quarter) to the Axis (Category) data binding slot, in that order, using the existing date hierarchy from the data model.
Open the Quick Functions menu for Sales Amount (gear icon) and select Same Period, YoY.
In the Inspector panel, expand the Title section and set the title to Year-over-Year Quarterly Sales Change.

In this configuration, the chart displays the difference between each quarter and the same quarter in the previous year. Rather than showing the original sales amount for each quarter, each column represents how much sales increased or decreased compared to the same quarter one year earlier.