Excel OFFSET function error when using TREND in reference

Question

Consider an Excel sheet with the following values:

   A   B
 --------
1| 1   5
2| 2   8
3| 3  11

Entering the array formula =TREND(B1:B3,A1:A3,A1:A3) in cells C1:C3 returns {5;8;11}, as expected. Entering =OFFSET(C1:C3,1,0) returns {8;11;0}, also as expected.

However, if I try entering =ROWS(OFFSET(TREND(B1:B3,A1:A3,A1:A3),1,0)), I get the message, "The formula you typed contains an error". I can't do anything to get it to accept the formula.

Next I created the named ranges "TrendRange" and "TrendFormula" with the formulae =Sheet1!$C$1:$C$3 and =TREND(Sheet1!$B$1:$B$3,Sheet1!$A$1:$A$3,Sheet1!$A$1:$A$3), respectively.

Again, =OFFSET(TrendRange,1,0) gives the correct result but =OFFSET(TrendFormula,1,0) does not (it results in #VALUE!).

There is a simple test that seems to always identify when OFFSET will have this issue. If =CELL("address", xxx) or =AREAS(xxx) result in #VALUE!, then the xxx section can't be used in OFFSET.

Is there any way around this? I've tried using LINEST and SLOPE/INTERCEPT instead of TREND, but I get the same result.

Answer 1

OFFSET requires a reference (a cell or a range as the first argument), it won't accept an array, so because a formula like

=TREND(B1:B3,A1:A3,A1:A3)

always returns an array, you can't use it as the first argument of OFFSET. Is this related to your previous question?