I. Soc. Cosmet. Chem., 24, 561-576 (August 19, 1973) Hair Product Evaluation: From Laboratory Bench to Consumer and Back Again DOREEN L. WEDDERBURN, B.S., and JOHN K. PRALL, Ph.D.* Presented December 11, 1972, New York City Synopsis--The need to validate and support advertising claims by means of scientific testing is growing in importance, and reliable instrumental methods of measuring product proper- ties are an essential part of any modern cosmetic program. The same methods can often be used to guide product development and to provide proof of efficacy, but they will only ful- fill their purpose if they yield data which correlate well with consumer perception of prod- uct attributes. Modern HAIR PRODUCTS are expected to fill many diverse needs and, in order to evaluate PERFORMANCE objectively, the cosmetic scientist must understand the words used by the consumer and be able to translate them into physical and measur- able terms. Recently developed PSYCHO-PHYSICAL and STATISTICAL TECHNIQUES are now available for unravelling words like "combability," "body," "control," and "set." These techniques permit us to establish quantitative relationships between INSTRUMENTAL evaluation in vitro and HUMAN EVALUATION. Quantitative psychological meanings can now also be assigned to instrumental readings of, e.g., combing resistance. More com- plex terms like body and control cannot at present be wholly quantified in psychological or instrumental terms, but we nevertheless know that body is made up of springiness, stiffness, and volume factors which may be measured instrumentally. Sensitive new techniques have been devised to measure key aspects of interfiber adhesion which influence springiness and stiffness, and extensive use of these methods has enabled us to establish and predict ranges of consumer acceptability by comparing the results of laboratory data with salon observa- tions and consumer response. INTRODUCTION Recent surveys of consumer needs have indicated that there is dissatis- faction with some hair products, and this is probably due to the fact that frequently claims have been made in advertising which may only apply in special circumstances. For example, some ot: the claims made for shampoos appear to lead the consumer to expect far more than simple cleansing ot: the *Unilever Research Laboratory, 455 London Road, Isleworth, Middlesex, England. 561

562 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS hair and, as will be recognized by members of the industry, many cosmetic shampoos actually do very little else, for the person with hair in good con- dition. A survey carried out in the USA in 1970 indicated that consumers expect shampoos to leave the hair shiny, make it manageable, soft and silky, give hair "body," prevent flyaway, and help damaged hair. These expectations are no doubt a reflection of advertising, and the comparatively recent boom in mar- kets for post-shampoo treatments, such as texturizers, setting lotions, condi- tioners, etc., may well indicate a general lack of consumer satisfaction with the attributes conferred by shampoos claiming to have special functions. Another survey carried out in the USA at about the same time related the benefit required with the proportion of dissatisfied users of a range of hair products. For example, it was noteworthy that whereas only half of the women interviewed were satisfied with setting aids, less than a quarter felt that the products claiming to confer body to hair lived up to their expectation. In general, the consumer is becoming more demanding, more suspicious of the cla:ms made in advertising, and more discriminating of product effective- ness and safety. Manufacturers are finding it increasingly difficult to produce new products which satisfy consumer needs. More relevant and more sensitive techniques of measuring product performance make the problem easier, how- ever, and evaluation science plays a key role in product development by: (a) indicating how consumers apprec'ate and iudge products in measur- able terms, (b) guiding the development and formulation of products which can be appreciated by consumers, (c) establishing permanent records of objective test data using standard- ized procedures, (d) sign-posting marketing strategy and providing technical support for advertising claims, and (e) predicting consumer response in laboratory tests and consumer trials. Four approaches to obiective evaluat:on may be used based on physical (1), sensory (2), chemical (3), and physiological (4) methods. However, onlv the first two have been employed regularly by cosmetic manufacturers. Typically, the physical approach involves the use of instrumental methods, and the sensory approach involves the use of trained human panels used as nstruments for sensing magnitudes of effects. Both the sensory and instrumen- tal methods can be highly quantitative and reproducible in both in vitro (using switches) and in vivo (salon) situations, provided standard conditions are always employed (5). Unlike in laboratory evaluation, the consumer is unable to judge products under standard conditions. In addition, certain groups of consumers may not be •nterested in, or sensitive to, particular product properties and this factor alone accounts for a large measure of the disagreement between instrumental