> A curious thing (well, to me!)... consider this template rule:

The <xsl:value-of> converts the booleans to strings; and the use of
xsl:variable with content creates a result tree fragment containing this
string as a child node. So you are quite right, test="$units_gt_300" would
always succeed, because it is testing whether the node-set equivalent to the
RTF contains any nodes: converting an RTF to a boolean always returns true
(despite what my book says on page 81 [sorry!].

But why don't you just write
<xsl:variable name="units_gt_300" select="units &gt; 300"/>
That way you get a variable whose type is boolean.