I have a list of users with the number of times they have been file checked in a 12 month period. I want to identify (in column H) how many consecutive months there has been NO file check for that user. Eg :

```
A B C D E F G
User |Oct |Nov | Dec | Jan | Feb | Mar
A | 0 | 1 | 1 | 0 | 0 | 0
B | 1 | 1 | 0 | 0 | 1 | 0
C | 0 | 0 | 1 | 0 | 0 | 0
D | 2 | 0 | 0 | 0 | 1 | 1
```

- Cell H2 should contain 3 as the there were no file checks on 3 consecutive months (Jan, Feb and March) for User A
- Cell H3 should contain 2 as there were no file checks on 2 consecutive months (Dec, Jan) for User B
- Cell H4 should contain 3 as the largest consecutive run of 0’s is 3 (Jan, Feb, Mar)
- Cell H5 should contain 3 as the there were no file checks on 3 consecutive months (Nov, Dec and Jan) for User D

I know a simple COUNTIF would give me the total number of 0’s for each user, but I want to calculate how many consecutive months and, where there has been more than one ‘block’ of consecutive 0’s, what the longest period is.

Inelegant, but it appears to work:

```
=MAX(IF(IFERROR(FIND(REPT("0",ROW($1:$6)),CONCAT($B2:$G2)),0),ROW($1:$6),0)) [Ctrl+Shift+Enter]
```

It iterates through the numbers yielded by `ROW($1:$6)`

to find the maximum number of zeroes in the concatenation of your per-month values in each row. Enter it as an array formula into H2 and fill down.

Tags: excelexcel, time