ahh sorry i dont know what it could be then, been a few years since i was taught, and dont really use it all that often anymore.
i use scale to increase /decrease the size of an object in a similar way to what your after, i think
if iv got an object 10 high that i want to increase to 15 but keeping ratios i do the following
i use scale, then click on an object, then type in 15/10 as the ratio and the object becomes 15 high
supposedly reference would give a similar outcome although you'd click on 2 seperate points of the object ( 10 apart), then type in its dimension e.g 15
i usually just search around on google to find commands if im not sure howw to do things, just type in basic description of whats required and see what pops up!