Andrew S. C. Ehrenberg

Andrew Ehrenberg is a Marketing Scientist. He has by half a century's work changed fundamentally the beliefs of marketing people both about the way consumer loyalty works and also about how advertising works.

Andrew Ehrenberg's fundamental belief is quite simply that the methods of physical science are also applicable to the social sciences. This principle has enabled him almost uniquely to establish wide-ranging empirical quantitative generalizations about human behavior.

Biography

Recently retired at the age of 80, Andrew Ehrenberg was born in Germany in 1926 into a well-known academic family. See Hans Philipp Ehrenberg [http://de.wikipedia.org/wiki/Hans_Ehrenberg] (Father), Victor Ehrenberg (historian) (Uncle), Geoffrey Rudolph Elton (Cousin). He came to England with his parents in 1938, and attended Queen's College, Taunton. Subsequently he studied statistics at Kings College, Newcastle-upon-Tyne and Cambridge.

In 1951 he became Lecturer in Statistics at the Institute of Psychiatry in London, and in 1955 moved into commercial marketing research and consulting, where his writings on statistical methodology in marketing research and wider fields soon became well-known. In 1970 he was invited to take the Chair of Marketing and Communication at the London Business School, where he remained for 23 years, eventually taking up a Research Chair.

In 1993 Andrew Ehrenberg became Professor of Marketing at the London South Bank University where he founded the Centre for Research in Marketing, and started the Research and Development Initiative which was funded by businesses internationally to pursue and disseminate quantitative marketing knowledge. The R. and D. I. became closely associated with the Marketing Science Centre at the University of South Australia and in 2004 Andrew Ehrenberg was succeeded as Director of the R. and D. I. by Professor Byron Sharp of the School of Marketing at UNISA. In 2005 Andrew Ehrenberg retired completely from the R. and D. I.

The Marketing Science Centre has now been expanded by the University of South Australia to form the Ehrenberg-Bass Institute for Research in Marketing and the former R. and D. I. has been incorporated into this.

Andrew Ehrenberg has the unique distinction of having been awarded the Gold Medal of the British Market Research Society twice, first in 1969 and again in 1996. He also holds the Honorary Fellowship of the Royal Statistical Society. In December 2005 he was awarded an Honorary Doctorate by the University of South Australia.

Andrew Ehrenberg has over 200 publications and six books to his credit, a number of them very often cited.

Research methods

An early interest in social science applications of statistics had already begun to show through in Cambridge (such as extensive experiments into the reliability of trained taste-testers for quality assessments and the into price subsidies in the food industry). Also developed were two early aversions, the first to multivariate techniques imposed on simple data, and the second to mathematics for its own sake in applied statistics.

Andrew Ehrenberg's belief that the methods of physical science are applicable to social science was expressed in an article in the hard science journal Nature (Ehrenberg 1993a) entitled "Even the social sciences have laws". In it he asserted that even in a field supposed to be dominated by people's impulses to buy, that of marketing, there are striking regularities.

The discovery and development of such lawlike relationships, was described in a paper to the Royal Statistical Society "The Discovery and Use of Laws of Marketing" (Ehrenberg 1969). In this he quotes five simple laws of buyer behaviour. The definitive statement of this position came later in another paper read to the Royal Statistical Society "Predictability and Prediction (Ehrenberg and Bound 1993b). The Summary stated baldly:

:A result can be regarded as routinely predictable when it has recurred consistently under a known range of different conditions. This depends on the previous analysis of many sets of data, drawn from different populations. There is no such basis of extensive experience when a prediction is derived from the analysis of only a single set of data. Yet that is what is mainly discussed in our statistical texts.

Andrew Ehrenberg has always pointed out that very many models of very different functional form may be generated with almost identical goodness of fit. The selection of an appropriate model form to express a quantitative relationship is governed in his view by the need for:

#Previous knowledge. This seems obvious but standard statistical modelling techniques seldom if ever start from any reference to any earlier model.
#Simplicity. Models with many parameters cannot be tested in their variations by new data.
#Adequate but not unnecessarily wide scope. Scope means the range of conditions in which the model has been found to apply. Empirical models are not of universal application. Decision on whether the scope is adequate depends on technical knowledge of the topic being modelled.
#The absence of bias in predictions. Closeness of fit is secondary to this. Exceptions to the model may be noted.
#A structural model, which remains meaningful under algebraic transformation. This rules out regression techniques - even simple regression produces two different equations.

The failure to use any technique of optimization either in model form selection or parameter determination has however been widely criticised. Andrew Ehrenberg has answered these criticisms by pointing to the absence of published and widely used models generated by conventional techniques. Another criticism is that Andrew Ehrenberg's published models deal with relationships between the averages of groups, and thus ignore variability between individuals.

The ideas in this section were used in one of Andrew Ehrenberg's principal fields of work, the study of buyer behaviour.

Buyer Behaviour

In 1955 Andrew Ehrenberg moved into marketing research working on consumer panels. He first milestone paper was "The Pattern of Consumer Purchases" (Ehrenberg 1959) which showed the applicability of the Negative Binomial Distribution to the numbers of purchases of a brand of consumer goods. The generalisation to the multi-brand case was put forward in ((The Dirichlet: A Comprehensive Model of Buying behaviour(( (Goodhardt, Ehrenberg and Chatfield 1984), read to the Royal Statistical Society. The Dirichlet model (Dirichlet_distribution) has become an important tool for many researchers. It applies widely and in fields other than fast-moving consumer goods, such as television viewing.

It has however been criticised as being based on steady-state conditions, in which market sizes and brand shares remain unchanged, and thus having no predictive or normative use. There are in different data sets substantial individual deviations between the observed and predicted values for some metrics for which there is at present no systematic explanation.

Andrew Ehrenberg has derived from these models of buyer behaviour a view on advertising for established brands. It mostly serves to publicise the advertised brand, but seldom seems to persuade. Promotions have only a short-term effect , and do not affect a brand's subsequent sales or brand loyalty. The extra buyers during the promotion have been seen almost all to have bought it before the promotion rather than being the hoped for new buyers.

Data reduction

This is another major strand in Andrew Ehrenberg's work. In 1975 he first published "Data Reduction". The book has been revised, reprinted and translated (Ehrenberg 1981). It maintains that much of the approach to research methods and prediction depends on finding patterns in data and this is much aided by its presentation in simple tables. Such tables also aid communication of results.

The basic ideas are very simple. They depend on the principles of how memory works: clear layout of simple tables, rounding of figures, placing figures to compared in the same column and showing averages.

This work has had a major effect in on the way data are presented in academia, commerce but less in the British public sector. There the layout of the official British Monthly Digest of Statistics under Sir Harry Campion antedated Andrew Ehrenberg by many years, but set a pattern in many ways the same.

Communication

Over more than fifty years Andrew Ehrenberg worked not only to discover new principles and understanding, nearly always using data already available. He worked just as hard to communicate - to write simply and understandably, and to present figures in such a way as to tell an understandable story. His tables and charts always supported his communication. They did not ask the readers themselves to undertake the work of extracting meaning from the data. In consequence they have been criticised as showing only carefully selected data.

Andrew Ehrenberg drafted and re-drafted, often to the exasperation of his collaborators. He was tireless in presenting and publicising his conclusions on both sides of the Atlantic, though recently to the present writer he observed that his own major failure was in effectively communicating his principles to the users of statistics. His work continues though to influence the practice of both statistical science and marketing.

References

These include some important papers not specifically mentioned above.

Barwise, P. and Ehrenberg, A. (1988), Television and its Audience, Sage, London, 1998.

Chatfield C., Ehrenberg, A. and Goodhardt, G. (1966), Progress on a simplified model of stationary purchasing behaviour, Journal of the Royal Statistical Society A, 129, 317- 367.

Ehrenberg, A., (1955) Measurement and mathematics in psychology, British Journal of Psychology, 46, 20-29.

Ehrenberg, A. (1959) The pattern of consumer Purchases, Applied Statistics, 8,1, 26-41.

Ehrenberg, A., (1964) Description, Prediction and Decision, Journal of the Market Research Society, 13, 14-33.

Ehrenberg, A., (1966) Laws in Marketing - A tailpiece, Journal of the Royal Statistical Society, Series C, 15, 257-268.

Ehrenberg, A., (1968) The Elements of lawlike relationships, Journal of the Royal Statistical Society, Series A, 131, 280-329.

Ehrenberg, A. (1969), The discovery and use of laws of Marketing, Journal of Advertising Research, 9,2, 11-17.

Ehrenberg, A. (1975,1981), Data Reduction, John Wiley, Chichester. Reprinted in the Journal of Empirical Generalisations in Marketing Science, 2000, 5, 1-391 (www.empgens.com).

Ehrenberg A.(1988) Repeat-buying: facts, theory and applications, 2nd ed., Edward Arnold, London; Oxford University Press, New York. Reprinted in the Journal of Empirical Generalisations in Mark Science, 2000, 5, 392-770 (www.empgens.com). Ehrenberg, A , Goodhardt, G. and Barwise, P (1990), Double jeopardy revisited, Journal of Marketing, 54, July, 82-91.

Ehrenberg, A. (1993a), Even the social sciences have laws, Nature, 365, 30 September, 385.

Ehrenberg A. and Bound, J. (1993b), Journal of the Royal Statistical Society Series A, 156, 2, 167-206.

Ehrenberg A., Hammond K. and Goodhardt G. (1994), The after-effects of price-related consumer Promotions, Journal of Advertising Research, 34,4, 11-21.

Ehrenberg, A., Barnard N., Kennedy R., and Bloom, H. (2002), Brand advertising ascreative publicity, Journal of Advertising Research, 42, 4, 7-18.

Ehrenberg, A. Uncles, M , and Goodhardt, G. (2004), Understanding Brand Performance Measures: Using Dirichlet Benchmarks, Journal of Business Research, 57, 12, 1307 - 1325.

Goodhardt G.J., Ehrenberg, A. and Chatfield (1984), The Dirichlet: A comprehensive model of buying behaviour, Journal of the Royal Statistical Society, Series A, 147, 621-655.

Goodhardt GJ, Ehrenberg A., Collins M. (1987), The television audience, 2nd ed. Gower, Aldershot, UK.

Scriven, J. and Ehrenberg A. (1999), Patterns of response to price changes, ANZMAC Conference Papers 1999.