Defining Consumer-Relevant Quality Boundaries for Body Lotion
Using DOSD to translate acceptable squeezability into product and viscosity specifications
The Challenge
Product specifications are often expressed in instrumental terms such as viscosity. But a technically meaningful change is not necessarily a consumer-relevant change.
For products dispensed from a tube or bottle, viscosity influences how easily the product can be squeezed out and used. Because viscosity can shift through formulation changes, processing and shelf life, product teams need to know not only the target value, but how far the product can move before dispensing becomes unacceptable to consumers.
The Approach
A series of lotion prototypes was created to systematically span viscosity levels above and below the current product reference.
Consumers evaluated one clearly defined question:
Is the product’s squeezability acceptable?
A two-step SDT-based acceptance judgement — acceptable/not acceptable followed by sureness — was used to quantify how much each prototype differed from the reference in acceptability. Instrumental rheological measurements were collected in parallel.
From consumer response to an operating range
The analysis identified which viscosity changes remained within an acceptable consumer range and where the risk of rejection started to increase.
By connecting those consumer boundaries to rheological measurements, an experiential judgement such as “this is becoming too difficult to squeeze” can be translated into a measurable range for formulation and quality control.
The result is not simply a preferred viscosity value, but an estimate of the operating space within which the product can vary while still delivering an acceptable consumer experience.
Decision value
Instead of specifying one ideal viscosity value, the product team can define a consumer-relevant operating window:
the range that supports acceptable product use;
the boundaries beyond which consumer risk increases;
and the margin available to accommodate formulation, manufacturing and shelf-life variation.
This gives product developers and quality teams a direct link between consumer tolerance and measurable technical specifications, rather than relying only on whether prototypes are statistically different.
Broader Principle
