I'm trying to write an expression in SSRS:

If today's **DAY** is <= 15th day, return pay period previous month 16th to last day of month 
If today's **DAY** is >= 16th day, return current month day 1st to 15th

This is the expression I have now but its not working: 

Start Date: 

```
=IIF(DAY(TODAY) <= 15, DateAdd(DateInterval.Day, 1-Day(Today), Today), DateAdd(DateInterval.Month, -1, (DateAdd(DateInterval.Day, 16-Day(Today), Today)))),
IIF(DAY(TODAY) >= 16, dateadd("m",0,dateserial(YEAR(Today),MONTH(Today),1)

```

End Date: 

```
=IIF(DAY(TODAY) <= 15, DateAdd(DateInterval.Day, -1, DateSerial(Year(Date.Now), Month(Date.Now), 1)),
IIF(DAY(TODAY) >= 16, dateadd(dd,datediff(dd,datepart(dd,getdate()),15),getdate())

```