# LAG

Returns the source value offset by a specific number of periods. The mode argument controls whether the source can be a non-positive value. Using a positive offset value for LAG refers to earlier periods, a negative value for LAG refers to later periods. A zero value refers to the current period.

The mode argument controls how a non-positive offset value will be treated; In *STRICT *mode the item to be offset is limited to a line item.

If the offset value is outside the model timescale, the fill value is used instead.

The mode options are *NONSTRICT*, *SEMISTRICT*, and *STRICT*.

*NONSTRICT*(default) allows positive, negative and zero values for offset.*SEMISTRICT*ignores negative values for offset and uses the fill value.*STRICT*ignores zero and negative values for offset and uses the fill value.

## Syntax

LAG(x, n, z,[mode])

where:

- x: value: Source line item to be offset
- n: offset: amount of offset
- z: fill: replacement entry if required
- [mode]:
*NONSTRICT*,*SEMISTRICT*, and*STRICT*: how the rule is applied

## Format

Input Format | Output Format |
---|---|

x: Number - Limited to line item in n: Number, line item z: Number Mode: NONSTRICT, SEMISTRICT, and STRICT |
Matches the data format used by argument x |

## Arguments

The function uses the following arguments:

- x: Number - Numeric line item
- n: Number - Numeric line item
- z: Number - Numeric line item
- [mode]: Keywords -
*NONSTRICT*,*SEMISTRICT*, and*STRICT*

## Constraints

The function has the following constraints:

- The time range providing arguments to a line item must match the time range for the result line item. Any formula that conflicts with this rule will be rejected. For more, see Search.
- A non-time series function, used as a sub-expression of this function, must use the same time range as the line item to which the formula is applied. Combining time series functions and non-time series functions with a time range could return an unexpected result or an error message. For more, see Time Ranges and Time Series Functions.

## Excel equivalent

- No Excel equivalent

## Example

In the example shown below, the formula in the *LAG* row returns the value from the *x* row from two periods before the selected cell. If the *x* value falls outside the range of the current model, the third parameter (0) is used, as seen in *Jan 15* and *Feb 15* columns. Because mode is not specified, it defaults to *NONSTRICT*.

**Note:**The

**Summary**column on the

*LAG*row uses the values for the preceding quarter, it does not apply the LAG formula.

LAG (x,2,0)

In this example shown below, the formula in the **LAG** row returns the value from the x row from two periods before the selected cell. If the *x* value falls outside the range of the current model, the value from the **z** column in the current period is used as seen in **Jan 15** and **Feb 15** columns.

LAG (x,2,z)