ISNA

Tests for the #N/A (Not Available) error value.

Syntax:

ISNA(value)

Returns TRUE if value is or refers to the #N/A (Not Available) error and FALSE otherwise.

Example:

ISNA(NA())

returns TRUE, because NA() returns the #N/A error.

ISNA(1/0)

returns FALSE, because 1/0 is a #DIV/0! error, not a #N/A error.

ISNA(A1)

where A1 contains "dog", returns FALSE, because "dog" is text, not an error.

Application:

Checking for Missing Data in a Sales Report

Imagine you're a data analyst for a retail company. You've been given a sales report that lists the weekly sales of various products. However, some of the sales figures are missing, and they show up as the #N/A error. You need to quickly identify which products have missing data so you can investigate and get the correct numbers.

The ISNA function is perfect for this. It will return TRUE if a cell contains the #N/A error and FALSE if it contains anything else.

Here's the data you have:

	Product	Week 1 Sales	Week 2 Sales	Week 3 Sales
	A	B	C	D
1	Laptop	$12,500.00	#N/A	$14,200.00
2	Smartphone	$8,900.00	$9,500.00	$10,100.00
3	Tablet	$5,200.00	#N/A	#N/A
4	Smartwatch	$3,100.00	$3,500.00	$3,900.00

Using the ISNA function:

To check for missing data in the "Week 2 Sales" column, you would create a new column called "Missing Week 2 Data?" and use the ISNA function.

For the first row (Laptop), the formula would be: ISNA(C1)

C1 contains #N/A.
The function returns TRUE.

For the second row (Smartphone), the formula would be: ISNA(C2)

C2 contains $9,500.
The function returns FALSE.

Applying this formula to the entire "Missing Week 2 Data?" column would produce the following table:

	Product	Week 1 Sales	Week 2 Sales	Week 3 Sales	Missing Week 2 Data?
	A	B	C	D	E
1	Laptop	$12,500.00	#N/A	$14,200.00	TRUE
2	Smartphone	$8,900.00	$9,500.00	$10,100.00	FALSE
3	Tablet	$5,200.00	#N/A	#N/A	TRUE
4	Smartwatch	$3,100.00	$3,500.00	$3,900.00	FALSE