Publications

In Pursuit of Enhanced Customer Retention Management: Review, Key Issues, and Future Directions

In today’s turbulent business environment, customer retention presents a significant challenge for many service companies. Academics have generated a large body of research that addresses part of that challenge—with a particular focus on predicting customer churn. However, several other equally important aspects of managing retention have not received similar level of attention, leaving many managerial problems not completely solved, and a program of academic research not completely align...

Customer Needs and Solutions, 5(12), 65-81.
Ascarza, E., Neslin, S., Netzer, O., Anderson, Z., Fader, P., Gupta, S., Hardie, B., Lemmens, A., Libai, B., Neal, D., Provost, F., and Schrift, R.

Unveiling the Relationship between the Transaction Timing, Spending and Dropout Behavior of Customers

The customer lifetime value combines into one construct the transaction timing, spending and dropout processes that characterize the purchase behavior of customers. Recently, the potential relationship between these processes, either at the individual customer level (i.e. intra-customer correlation) or between customers (i.e. inter-customer correlation), has received more attention. In this paper, we propose to jointly unveil the direction and intensity of these correlations using copulas. We...

International Journal of Research in Marketing, 32, 78–93. [*Equal contribution]
*Glady, N., Lemmens, A., and Croux, C.

Polymorphisms of the OXTR Gene to Explain Why Sales Professionals Love to Help Customers

Polymorphisms of the OXTR gene affect people’s social interaction styles in various social encounters: carriers of the OXTR GG, compared to the OXTRAA/AG in general, are more motivated to interact socially and detect social salience. We focus on sales professionals operating in knowledge intensive organizations. Study 1, with a sample of 141 sales people, shows that carriers of the OXTR GG allele, compared to the OXTR AA/AG allele, a...

Frontiers in Behavioral Neuroscience, 7(171), 1-13.
Verbeke, W.J.M.I., Bagozzi R.P., van den Berg W., and Lemmens, A.

Dynamics in International Market Segmentation of New Product Growth

Prior international segmentation studies have been static in that they have identified segments that remain stable over time. This paper shows that country segments in new product growth are intrinsically dynamic. We propose a semiparametric hidden Markov model to dynamically segment countries based on the observed penetration pattern of new product categories. This methodology allows countries to switch between segments over the life cycle of the new product, with t...

International Journal of Research in Marketing, 29(1), 81-92.
Lemmens, A., Croux, C. and Stremersch, C.

Analytics for Customer Engagement

In this article, we discuss the state of the art of models for customer engagement and the problems that are inherent to calibrating and implementing these models. The authors first provide an overview of the data available for customer analytics and discuss recent developments. Next, the authors discuss the models used for studying customer engagement, where they distinguish the following stages: customer acquisition, customer development, and customer retention. Finally, they discuss severa...

Journal of Service Research, 13(3), 341-356.
Bijmolt, T.H.A., Leeflang, P.S.H, Block, F., Eisenbeiss, M., Hardie, B.G.S., Lemmens, A. and Saffert, P.

Sales Growth of New Pharmaceuticals across the Globe: the Role of Regulatory Regimes

Prior marketing literature has overlooked the role of regulatory regimes in explaining international sales growth of new products. This paper addresses this gap in the context of new pharmaceuticals (15 new molecules in 34 countries) and sheds light on the effect regulatory regimes have on new drug sales across the globe. Based on a time-varying coefficient model, we find that differences in regulation substantially contribute to cross-country variation in sales. One of the regulatory constra...

Marketing Science, 28(4), 690-708. [*Equal contribution]
*Stremersch, S. and Lemmens, A.

Measuring and Testing Granger Causality over the Spectrum: An Application to European Production Expectation Surveys

Decomposing Granger causality over the spectrum allows us to disentangle potentially different Granger causality relationships over different frequencies. This may yield new and complementary insights compared to traditional versions of Granger causality. In this paper, we compare two existing approaches in the frequency domain, proposed originally by Pierce [Pierce, D. A. (1979). R-squared measures for time series. Journal of the American Statistical Association, 74, 901...

International Journal of Forecasting, 24(3), 414-431.
Lemmens, A., Croux, C. and Dekimpe, M.G.

Consumer Confidence in Europe: United in Diversity?

The ongoing unification taking place in the European political scene, along with recent advances in consumer mobility and communication technology, raises the question of whether the European Union can be treated as a single market to exploit potential synergy effects from pan-European marketing strategies. Previous research, which mostly used domain-specific segmentation bases, has resulted in mixed conclusions.

In this paper, a more general segmentation basis is adopted, as we consid...

International Journal of Research in Marketing, 24 (2), 113-127.
Lemmens, A., Croux, C. and Dekimpe, M.G

Consumer Sentiment and Consumer Spending: Decomposing the Granger Causal Relationship in the Time Domain

It is often believed that the consumer sentiment index has predictive power for future consumption levels. While Granger causality tests have already been used to test for this, no attempt has been made yet to quantify the predictive power of the consumer sentiment index over different time horizons. In this article, we decompose the Granger causality at different time lags, by looking at a sequence of nested prediction models. Since the consumer sentiment index turns out to be cointegrated w...

Applied Economics, 39, 111.
Gelper S., Lemmens A. and Croux C.

Trimmed Bagging

Bagging has been found to be successful in increasing the predictive performance of unstable classifiers. Bagging draws bootstrap samples from the training sample, applies the classifier to each bootstrap sample, and then averages overal lobtained classification rules. The idea of trimmed bagging is to exclude the bootstrapped classification rules that yield the highest error rates, as estimated by the out-of-bag error rate, and to aggregate over the remaining ones. In this note we explore th...

Computational Statistics and Data Analysis, 52 (1), 362-368.
Croux, C., Joossens, K. and Lemmens, A.