How do packaging size changes get perceived by the consumer? Can you optimize either the length or height of a package and eliminate wasteful packaging of air?
There is a simple thumb rule, tested in various researches, which best approximates consumer perceptions of size changes.
The truth: People underestimate the surface area (of 2 dimensional) or the volume (of 3 dimensional products). This is especially so when you change more than one dimension at the same time.
The Model: People relate the new pack in comparison with the old reference, and, they determine changes additively (and not multiplicatively).
(1 + % increases) / (1 + % decreases) = Size in relation to reference.
This is applicable to two dimensional products and can also be applied to the front face of the package.
Look at the example below of a square of sides 10 cm and another of 12 cm. It has been noticed that the smaller object is always assumed to be the reference for the % increase – 20% in our case.
While the bigger square is techincally 44% bigger, the perception would most likely be that it is only 40% bigger.
Also despite there being a 30.5% decrease from the larger square, the smaller square would have perceived to have shrunk only by about 28.5%.
Further implications and uses
While the differences shown above may seem small, this further gets magnified as you add another dimensions, which is the case in most packaging.
So, a box that has had its length increased by 20%, width by 30% and reduced in height by 10% – which is actually a 40% increase, would be perceived to have increased by just 36%.
(1 + .2 + .3) / (1 + . 1) = 1.36
Go ahead try finding out the optimum size for your packs! – worth a try especially if you have good estimates of pack size decrease vs. % fall in demand.
Further Recommended Reading:
The AddChange heuristic model, Balakrishnan and Eliashberg, 1995