A Derivative Based Estimator for Semiparametric Index Models

This paper proposes a semiparametric estimator for single- and multiple index models.It provides an extension of the average derivative estimator to the multiple index model setting.The estimator uses the average of the outer product of derivatives and is shown to be root-N consistent and asymptotically normal. Unlike the average derivative estimator, our estimator still works in the single-index setting when the expected derivative is zero (symmetry).Compared to other estimators for multiple index models, the proposed estimator has the advantage of ease of computation.While many econometric models can be regarded as multiple index models with known number of indices, our estimator in addition provides for a natural framework within which to test for the number of indices required.econometric models;kernel estimator;ranking;semiparametric estimation

A method of moments estimator for semiparametric index models

We propose an easy to use derivative based two-step estimation procedure for semi-parametric index models. In the first step various functionals involving the derivatives of the unknown function are estimated using nonparametric kernel estimators. The functionals used provide moment conditions for the parameters of interest, which are used in the second step within a method-of-moments framework to estimate the parameters of interest. The estimator is shown to be root N consistent and asymptotically normal. We extend the procedure to multiple equation models. Our identification conditions and estimation framework provide natural tests for the number of indices in the model. In addition we discuss tests of separability, additivity, and linearity of the influence of the indices.Semiparametric estimation, multiple index models, average derivative functionals, generalized methods of moments estimator, rank testing

Dynamic and Competitive Effects of Direct Mailings

We propose a dynamic direct mailing response model with competitive effects, where purchase and promotion history are incorporated. We then map the dynamic competitive interactions amongst the firms sending the mailings. We investigate the short- and long-run impact of a direct mailing on the revenues of the firm sending the mailing and on the revenues of its competitors. The model accounts for unobserved heterogeneity across households. We estimate the model in the charitable giving setting, as sending direct mailings represents a large part of charitable fundraising activity. Households often receive direct mailings of different charities within a short period of time and competition is highly relevant. We construct a unique database by merging the databases of three large charity organizations in the Netherlands. This results in household level data on the direct mailings received and the donations made by each household to each charity. Our results show that charitable direct mailings are short-run complements, that is, the direct mailings tend to increase the total pie that is divided among the charities. At the same time, the charitable direct mailings are long-run substitutes. In the long run they fight for a piece of the pie that households have available for charitable giving.Competition;Dynamics;Direct Mailings

Irritation Due to Direct Mailings from Charities

Direct mailing is the main tool that charities employ for fundraising. With increasing amounts of soliciting mailings and with the best donators receiving more mailings as a result of target selection, irritation might increase. As a result, such irritation could cause individuals to donate less, and hence reduce revenues for charities. We develop a conceptual model, which relates donating behavior to irritation and to mailing frequencies. We consider mailing frequencies relative to a reference point, which we call the maximum acceptance level. Furthermore, we allow for asymmetric effects of positive and negative differences with this maximum acceptance level, and hence we consider the effects of receiving excessive and acceptable amounts of mailings. To test our model empirically, we conduct a survey on charitable direct mailings and donating behavior among 213 respondents. We find that too many mailings do indeed lead to irritation, and that such irritation reduces annual donations.DM;Direct Mail;Irritation;Junk Mail

Do Charities Get More when They Ask More Often? Evidence from a Unique Field Experiment

Charitable organizations send out large volumes of direct mailings, soliciting for money in support of many good causes. Without any request, donations are rarely made, and it is well known that each request for money by a charity likely generates at least some revenues. Whether a single request from a charity increases the total amount donated by an individual is however unknown. Indeed, a response to one request can hurt responses to others. The net effect is therefore not easily observable, certainly not when multiple charities address the same individuals. In this paper we alleviate these observational difficulties by carrying out a field experiment in which five large charities cooperate. With the unique data that we collect, we study the impact of sending more requests on total donations. The results indicate that there is a negative competitive effect on requests from other charities, but this effect dies out rapidly. Soon after the mailing has been sent, it is only a strong cannibalization of the charity’s own revenues that prevails. This empirical finding suggests the important conclusion that not much coordination across charities is needed to increase revenues. We also demonstrate that charities need sophisticated evaluation tools that do not ignore the effects of cannibalization.competition;field experiment;direct mailing;fundraising

Does Irritation Induced by Charitable Direct Mailings Reduce Donations?

Charities mainly rely on direct mailings to attract the attention of potential donators. Individuals may feel irritated by these mailings, in particular when they receive many mailings. We study the consequences of perceived irritation on stated behavior and on actual behavior. Target selection by charities likely results in good donators receiving many mailings and hence they might also be most irritated. Therefore, irritation with direct mailings might be endogenously determined. To create exogenous variation in irritation, we design a unique controlled field experiment in cooperation with five of the largest charities in the Netherlands. Our analysis reveals that direct mailings do result in irritation, but surprisingly this affects neither stated nor actual donating behavior.direct marketing;field experiment;charity donations;irritation