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    MASTER IN TOURISM AND ENVIRONMENTALECONOMICS

    (MTEE)

    Econometrics

    Final Exam Microeconometric Part

    ARE EDUCATION LEVEL AND SPORTS

    ACTIVITIES DETERMINANTS OF HEALTH CAREUTILIZATION IN GERMANY?AN ECONOMETRIC APPROACH WITH A HURDLEMODEL

    ByItalo Arbul Villanueva

    January 2010

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    INDEX

    1. INTRODUCTION ....................................................................... 3

    2. LITERATURE REVIEW ............................................................. 42.1. The Grossman Model ............................................................. 4

    2.2. The Zweifel Model .................................................................. 6

    3. ECONOMETRIC SPECIFICATION ........................................... 83.1. The Hurdle Specification ...................................................... 10

    4. DATA ...................................................................................... 12

    5. RESULTS ............................................................................... 15

    6. MAIN CONLUSIONS .............................................................. 23

    7. BIBLIOGRAPHY AND SOURCES .......................................... 25

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    1. INTRODUCTION

    This paper models the demand for health services in Germany measured as the number

    of visits to a doctor. At the present time, it is important to understand the decision-

    making process to obtain a better evaluation of the socioeconomic forces that cause the

    increase in health care utilization (POHLMEIER and ULRICH, 1995).

    Germany has a highly state-financed health-care system like most nations, and

    subsequently the results obtained with this work will be appropriate to use in other

    countries with policy purposes. Specifically, this work seeks to determine if citizens

    actively engaged in sports and the level of education are driven forces in the health

    service demand.

    Having a clear idea of both, health care demand determinants and the magnitude of their

    effects will help to give some advices to public authorities in order to achieve a healthier

    society.

    In the Health Economics literature the first health care demand model was formulated by

    GROSSMAN (1972). It is based on the traditional consumer theory and considers the

    individual as a sole agent or a prime decision maker in the process of health care

    utilization.

    The second approach of this process is to assume that the demand for health services is

    made in two stages: the contact decision and the intensity of use decision. This model

    developed by ZWEIFEL (1981) is based on the principal-agent framework.

    This work will take into account these two approaches through the use of specific

    instruments, in this sense, the Hurdle Model is appropriate for the purpose of this study.

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    2. LITERATURE REVIEW

    The theoretical approaches capable of application to the analysis of health care

    utilization are two: (i) The traditional consumer theory (Grossman, 1972), which

    considers the individual as the primary agent to determine the demand for health

    services, but conditioned by the organization of the health system and, (ii) principal-

    agent models, in which the physician as agent of the patient, determines the amount of

    medical services used on behalf of the patient (principal) once it has produced the first

    visit. (Zweifel, 1981).

    The contribution of Pohlmeier and Ulrich (1995) is the combination of both approaches to

    tackle the demand for health services as a process consisting of two stages.

    2.1. The Grossman Model

    Grossman (1972) presents a model as a result of his concern about the demand for

    health services and the distinction between the concepts of health and medical services,

    considering the first as a basic good in consumer demand, while medical services are

    inputs, the result of a derived demand, to produce more health.

    Grossman believes that each individual tries to maximize an inter-temporal utility

    function, based on a set of consumer goods Zt, and the total consumption of "health

    services", ht, understood as the time variable produced by healthy level health, Ht:

    The stock of health changes over time depending on the investment I t, and the rate of

    depreciation of health t, as shown by the following relationship:

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    Consumers can be considered as producers of those services that increase their utility

    levels, buying inputs from the market, and combining them with their own time. These

    production functions are expressed as:

    where M is a vector of inputs that, according to Grossman, contribute to the gross

    investment in health care; TH is the time taken to improve health; X are market inputs

    for the production of good Z, T represents the free time spent on produce those goods,

    and E is the exogenous level of education, which operates as an efficiency factor in the

    production function.

    The consumer faces two constraints: time and budget constraints. As regards the first,

    the total amount of time (t) is divided into time spent on: production of health (THt) and

    other assets (Tt), work (TWt) and time lost due to illness (TSt). Regarding to the second

    constraint, that income must match the costs they incurred for the production of health

    and other goods:

    where ptx y pt

    m are prices of inputs X and healthcare M, respectively, w t is the wage rate

    per hour, i is the interest rate for present value, and A0 is the discounted value of

    unearned income (non-labor income) or endowments.

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    The quantities of balance between goods Ht and Zt are obtained by maximizing the

    function utility and production functions subject to the restrictions already mentioned.

    The optimal value is reached when the marginal benefits are equal to the marginal costs

    of gross investment in health.

    It is expected that wage increases lead to an increase of income realized by healthy

    days that will encourage individuals to invest more in health care and demand more

    health care services. The price of health services will have special significance in the

    demand for private services, so that increasing them will have negative effects onconsumption. In the case of analyzing public health systems demand, the price is

    replaced by variables representing the cost of time or access.

    With respect to education, people with more education increases the marginal product of

    the inputs used and, therefore, reduce the necessary amount of them to produce the

    same amount of health. On the other hand, the age will reduce the health status and,

    consequently, increase medical costs.

    2.2. The Zweifel Model

    The economic model of physician behavior developed by Zweifel (1981), unlike the

    Grossman Model, is characterized by the fact that is the physician, as agent of the

    patient, who determines the necessary amount of health services on behalf of the patient

    (principal) once it has produced the first visit.

    This model states that the physician not only determines the treatment according to

    clinical and ethical criteria (I), but also stems from economic incentives, such as income

    (Y) or leisure (L). The utility function is represented by the following expression:

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    Where s is an unknown parameter that represents the average level of symptoms.

    While it is difficult to specify conduct that would constitute an unethical behavior, this is

    set (approximated) according to whether the compensation in terms of income and

    leisure is large enough.

    Note that only the demand for first visits is under the control of patients. Once the first

    contact occurs, the physician is free to choose the number of visits, either by visits of

    longer or shorter duration, or varying the frequency of the visits on patient or refer the

    patient to another level of assistance.

    The usefulness of this theoretical model for empirical applications is specified in

    separate analysis of the use, depending on whether a decision taken by the patient or

    determined by the healthcare professional in accordance with that agency relationship.

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    3. ECONOMETRIC SPECIFICATION

    Count data models represent a natural starting point for estimating the demand for

    health services, measured as the number of visits to the doctor during a given time

    interval.

    Unlike more popular approaches for qualitative endogenous variables such as logit and

    probit, count data approaches assume a dependent variable resulting from a discrete

    probability function. For our specific application this implies that we are mainly interested

    in an explanation of the number of visits to a doctor per se.

    A widely used count data model is based on the Poisson distribution. This model can be

    characterized by a single parameter, implying the equality of the conditional mean and

    the conditional variance. However, the equidispersion property turns out to be too

    restrictive for most empirical applications. In the following, we assume that our

    dependent variable stems from a negative binomial data generating process.

    Assuming a random variable Y, which can take only nonnegative integer values, the

    probability that exactly y counts are observed is given under the Poisson assumption by:

    The negative binomial distribution for Y can be derived as a compound Poisson process

    where the parameter of the Poisson distribution is specified as a gamma distributed

    random variable:

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    Integration over yields the negative binomial distribution for Y (see Cameron and

    Trivedi 1986):

    Since and v are positive it is clear that the variance exceeds the mean. Hence, the

    model allows for overdispersion, a fact that characterizes many data sets.

    This model has been used by Cameron et al. (1988) to explain the number of visits to

    the doctor, number of hospital admissions, days of stay and number of drugs consumed

    in Australia; Pohlmeier and Ulrich (1995) have applied this model to analyze the number

    of visits to general practitioners and specialists in Germany; and Gerdtham (1997) used

    the model to analyze medical visits and weeks of hospital stay in Sweden.

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    3.1. The Hurdle Specification

    Health economic considerations suggest that the decision to contact a doctor and the

    decision about the length of treatment are based on different decision-making

    processes, since the contact decision solely depends on the individual, while the

    frequency of visits also reflects the supply of health services given by the doctor.

    The main attractiveness of this model is given in part by a fundamental characteristic of

    the demand for health care services, which is the high percentage of non-use. In addition

    to its connection with the principal-agent models (Zweifel, 1981), in which the doctor (

    agent) determines the utilization on behalf of the patient (principal) once the initial

    contact has been made.

    The contribution of Pohlmeier and Ulrich (1995) to empirical modeling lies in the

    consideration of decision making as a two-step process. The first is the patient who

    decides to visit the doctor but once the doctor comes in, it is he who determines the

    intensity of treatment in the second stage.

    The two-part models distinguish between "users" and "non-users" of the health

    service. The "non-users" are those that show a zero use in the study period. In this

    context, the first stage models the division between "non-users" (zero) and "users"

    (positive) based on binary regression models, this means that at this stage estimates the

    probability of accessing the service.

    The second stage models the use or frequency for those with a positive level of use byemploying a model "count data" for truncated data. The structure of the models in two

    parts is applied to both discrete and continuous variables. When applied to the first kind

    of variables, the model is often called "Hurdle model."

    A Hurdle model suggests that the processes generating the zeros (not going to the

    doctor) and positive values (visit the doctor) are different. The model combines the zeros

    of a distribution function with positive values of another distribution function.

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    In this work we use to model the first stage a probit model and, for the second stage, the

    negative binomial model with truncated data (positive values).

    The specification of the two processes of decision is made with the same explanatory

    variables, but the results must be interpreted differently, depending on the stage. The

    likelihood function for this model is expressed:

    The first factor is estimated using a binomial probability model and indicates that there is

    no any contact with health services. The first term of the second factor represents the

    probability of making one or more visits, while the ratio measures the likelihood that a

    positive event occurs conditional on the completion of a contact.

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    4. DATA

    Our data source is the German Socioeconomic Panel Survey (SOEP) realized in 1999.

    The SOEP is a household based study which started in 1984 and which reinterviews

    adult household members annually. The annual surveys are conducted by the German

    Institute for Economic Research (DIW Berlin). The survey is funded by the German

    Federal Government and the State of Berlin via the Bund-Lnder Commission for

    Educational Planning and Research Promotion

    The size of the sample is 6,231 individuals. The survey was conducted by direct

    interviews. The dependent variable of our study is the number of visits to a doctor in the

    three months before the interview.

    The panel includes a wide range of micro- level information on socioeconomic

    characteristics of individuals and households, including specific variables on working and

    living conditions as well as variables on health conditions and health care utilization.

    The variables are shown in the following tables which contains the definition and a

    summary of the main statistics of those variables.

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    Data organization

    doctco number of doctor visits in last three months

    age age in years

    male male = 1; female = 0

    educ years of schooling

    married married = 1; otherwise = 0

    hsize number of people living in household

    sport actively engaged in sports = 1; otherwise = 0

    goodh good health (self assessment) = 1; otherwise = 0

    badh bad health (self assessment) = 1; otherwise = 0

    sozh individual receives welfare payments = 1; otherwise = 0

    loginc logarithm of monthly gross income

    ft full time work = 1; otherwise = 0

    pt part time work = 1; otherwise = 0

    unemp unemployed = 1; otherwise 0

    winter interview in winter quarter = 1; otherwise = 0

    spring interview in spring quarter = 1; otherwise = 0

    fall interview in fall quarter = 1; otherwise = 0

    doctcod 1 = did visit doctor in last three months; 0 otherwise.

    age2 age - squared

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    VARIABLE Mean Median Maximum Minimum Std. Dev. Skewness Kurtosis

    DOCTCO 2.39 1.00 60.00 0.00 3.94 4.98 45.18

    AGE 38.92 37.00 60.00 20.00 11.23 0.27 1.99

    MALE 0.47 0.00 1.00 0.00 0.50 0.14 1.02

    EDUC 11.33 11.00 18.00 7.00 2.36 0.94 4.38

    MARRIED 0.65 1.00 1.00 0.00 0.48 -0.62 1.39

    HSIZE 3.09 3.00 11.00 1.00 1.33 0.73 4.37

    SPORT 0.27 0.00 1.00 0.00 0.44 1.06 2.12

    GOODH 0.58 1.00 1.00 0.00 0.49 -0.32 1.10

    BADH 0.13 0.00 1.00 0.00 0.34 2.21 5.89

    SOZH 0.03 0.00 1.00 0.00 0.18 5.25 28.58

    LOGINC 6,982,553.00 7,476,104.00 9,420,332.00 8.57 1,878,661.00 -2.91 10.05

    FT 0.54 1.00 1.00 0.00 0.50 -0.15 1.02

    PT 0.11 0.00 1.00 0.00 0.32 2.42 6.88

    UNEMP 0.07 0.00 1.00 0.00 0.26 3.23 11.45

    WINTER 0.32 0.00 1.00 0.00 0.47 0.79 1.62

    SPRING 0.53 1.00 1.00 0.00 0.50 -0.13 1.02

    FALL 0.01 0.00 1.00 0.00 0.12 8.44 72.19

    DOCTCOD 0.65 1.00 1.00 0.00 0.48 -0.65 1.42

    AGE2 1640.81 1369.00 3600.00 400.00 915.65 0.64 2.26

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    5. RESULTS

    The first equations (first-stage decision) which represent the decision process made by

    the principal (patient) to visit the doctor were estimated through a probit model, the

    following table shows the results.

    Dependent Variable: DOCTCODMethod: ML - Binary Probit (Quadratic hill climbing)Date: 01/17/10 Time: 02:05

    Sample: 1 6231Included observations: 6231Convergence achieved after 12 iterationsCovariance matrix computed using second derivatives

    Variable Coefficient Std. Error z-Statistic Prob.

    C 1.203106 0.252049 4.773301 0.0000AGE -0.026998 0.012675 -2.129953 0.0332AGE2 0.000328 0.000155 2.116699 0.0343EDUC 0.014512 0.007462 1.944741 0.0518

    MARRIED 0.122406 0.043448 2.817321 0.0048HSIZE -0.064512 0.014172 -4.552100 0.0000SPORT 0.116645 0.039531 2.950688 0.0032GOODH -0.488356 0.039590 -12.33530 0.0000BADH 0.559279 0.067412 8.296379 0.0000SOZH 0.016492 0.098910 0.166736 0.8676

    LOGINC 6.55E-09 9.01E-09 0.727023 0.4672FT -0.275771 0.042508 -6.487591 0.0000PT 0.011880 0.062702 0.189468 0.8497

    UNEMP -0.297365 0.070312 -4.229238 0.0000WINTER -0.027029 0.054082 -0.499779 0.6172SPRING 0.015579 0.050587 0.307972 0.7581

    FALL 0.340272 0.162125 2.098821 0.0358

    Mean dependent var 0.653988 S.D. dependent var 0.475735S.E. of regression 0.456797 Akaike info criterion 1.208380Sum squared resid 1296.633 Schwarz criterion 1.226762Log likelihood -3747.709 Hannan-Quinn criter. 1.214751Restr. log likelihood -4018.639 Avg. log likelihood -0.601462LR statistic (16 df) 541.8595 McFadden R-squared 0.067418Probability(LR stat) 0.000000

    Obs with Dep=0 2156 Total obs 6231Obs with Dep=1 4075

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    As we can appreciate in the table, the McFadden R-squared is very low (0.067), this

    means that the variables included in the model are not enough to explain the probability

    of visiting the doctor. In this sense, there are other variables that should be taken into

    account but are not included on the survey, for example, the fact that the individual has a

    private health insurance.

    The second equation (second-stage decision) represents the decision process made by

    the agent (doctor) about the number of necessary visits that the principal (patient) should

    do. This model was estimated through a count data model which used a negative

    binomial distribution, the following table shows the results.

    It is important to remember that in count data models, in which the dependant variables

    takes integers positive values, the most useful methods to estimate the coefficients are

    the use of the Poisson distribution and the negative binomial distribution. However, the

    use of Poisson distribution imposes some restrictions; the most important restriction is

    the equality of the (conditional) mean and variance. However, this assumption is often

    violated in empirical applications. When this his restriction does not hold, it is better touse the negative binomial distribution.

    E-Views estimate the logarithm of the measure of the extent to which the conditional

    variance exceeds the conditional mean, and labels this parameter as the "SHAPE"

    parameter in the output. Therefore, is this parameter is statistically equal to zero (accept

    the null hypothesis) the Poisson distribution should be used; otherwise, the negative

    binomial distribution would be a better choice.

    As we can see in the estimation output of the second stage, the parameter SHAPE is

    statistically different from zero; this means that the choice of the negative binomial

    distribution was a correct choice in order to estimate the number of visits to the doctor.

    It is important to consider that in this regression the adjustment coefficient (measured by

    the Pseudo-R2) is also low (0.24) which also leads to the conclusion that the number of

    visits to the doctor have other determinants that maybe are not related with

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    socioeconomic variables but to variables related with the necessary treatment of the

    patient (for example, a patient with flu should have less number of visits than a patient

    whit a broken leg or heart diseases).

    Dependent Variable: DOCTCO

    Method: ML - Negative Binomial Count (Quadratic hill climbing)

    Date: 01/16/10 Time: 19:56

    Sample: 1 6231 IF DOCTCOD=1

    Included observations: 4075

    Convergence achieved after 12 iterations

    Covariance matrix computed using second derivatives

    Coefficient Std. Error z-Statistic Prob.

    C 1.563108 0.197797 7.902606 0.0000

    AGE 0.003744 0.009606 0.389800 0.6967

    AGE2 -4.73E-05 0.000115 -0.410315 0.6816

    EDUC -0.013015 0.005733 -2.270132 0.0232

    MARRIED 0.023284 0.033088 0.703712 0.4816

    HSIZE -0.042016 0.011141 -3.771298 0.0002

    SPORT 0.023491 0.030199 0.777874 0.4366

    GOODH -0.349505 0.030214 -11.56781 0.0000

    BADH 0.605303 0.035395 17.10127 0.0000

    SOZH 0.139548 0.070566 1.977549 0.0480

    LOGINC 5.45E-09 6.87E-09 0.793319 0.4276

    FT -0.175504 0.031013 -5.659066 0.0000

    PT -0.225013 0.044650 -5.039540 0.0000

    UNEMP -0.153783 0.053371 -2.881392 0.0040

    WINTER 0.009389 0.041715 0.225063 0.8219

    SPRING -0.023857 0.039093 -0.610246 0.5417

    FALL 0.013600 0.106748 0.127406 0.8986

    Mixture Parameter

    SHAPE:C(18) -1.023684 0.035730 -28.65024 0.0000

    R-squared 0.140521 Mean dependent var 3.655706Adjusted R-squared 0.136920 S.D. dependent var 4.376656

    S.E. of regression 4.066006 Akaike info criterion 4.491873

    Sum squared resid 67071.97 Schwarz criterion 4.519757

    Log likelihood -9134.192 Hannan-Quinn criter. 4.501748

    Restr. log likelihood -12072.05 Avg. log likelihood -2.241519

    LR statistic (17 df) 5875.716 LR index (Pseudo-R2) 0.243360

    Probability(LR stat) 0.000000

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    18181818

    In order to examine the marginal effects of a variable, we must examine the change in

    the unconditional medical visits mean given a change in an explanatory variable which

    is:

    The first part of the previous equation is the change in the conditional mean of medical

    visits weighted by the probability of making a visit to the doctor and the second part is

    the change in the probability of taking a non-zero health care demand weighted by the

    conditional mean of medical visits. The following chart shows the marginal effects for

    the first stage (probit model), the second stage (count data model using a negative

    binomial distribution) and for the whole estimation (Hurdle model).

    Marginal Effect of Explanatory Variables

    Variable PROBIT NEG-BIN HURDLE

    C 0.784296 7.461712 7.730783

    AGE -0.017600 0.000000 -0.064326

    AGE2 0.000214 0.000000 0.000781

    EDUC 0.009460 -0.011233 0.027254

    MARRIED 0.079795 0.000000 0.291647

    HSIZE -0.042055 -0.036992 -0.177824

    SPORT 0.076040 0.000000 0.277921

    GOODH -0.318356 -0.293832 -1.355117

    BADH 0.364590 0.673028 1.771292

    SOZH 0.000000 0.140180 0.091382

    LOGINC 0.000000 0.000000 0.000000

    FT -0.179773 -0.160743 -0.761846

    PT 0.000000 -0.218765 -0.142611

    UNEMP -0.193850 -0.152126 -0.807679

    WINTER 0.000000 0.000000 0.000000

    SPRING 0.000000 0.000000 0.000000

    FALL 0.221821 0.000000 0.810740

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    19191919

    It is important to mention that in this work we used a 10% confidence level, in this sense,

    the variables that which coefficients were not statistically significant for this confidence

    level were replaced by zeros.

    We find a quadratic relationship between the decisions of visit the doctor (DOCTORD)

    and the age of the agent since this variable and the age-squared are significant variables

    in this model, this means that for the first stage, age is a significant variable. However,

    for the second stage this variable does not explain the decision of the number of visits.

    Furthermore, Education (measured as the number of years of schooling) is a significantvariable for both stages1, however, for the first stage this variable has a positive effect

    while for the second stage, this variables has a negative effect. It is possible to find in

    the literature arguments for both effects.

    Grossman explained that educated people increases the marginal product of the inputs

    used and, therefore, reduce the necessary amount of them to produce the same amount

    of health. In this sense, as Pohlmeier and Ulrich mentioned, once the patient has

    visited the doctor and know which is his health problem and the necessary treatment, he

    can take care of himself in a better way and can improve their health more efficiently

    than less educated patients, this leads to less number of visits in the future, as the

    marginal effect of this variable measures for the Hurdle model.

    Marital status (MARRIED) is also an explanatory variable for the first stage, this means

    that it is more probably that married people decide to visit a doctor; this could be

    explained by the fact that married couples tend to promote the visits to the doctor when

    the husband or wife fell any kind of illness. However, the marital status is not a

    statistically significant variable on the second stage; this means that marital status has

    no effect over the number of visits to the doctor. On the other hand, referring also to the

    family characteristics, we found that for both stages, the family size have a statistically

    negative impact.

    1At a 10% confidence level.

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    20202020

    In the case of people actively engage with sports activities it is interesting to appreciate

    that this group are more likely to visit the doctor as a first stage decision. However, this

    variable (SPORTS) is not a significant variable on the second stage. This could be

    explained by the fact that people who are actively engaged in sports tend to care more

    about their health status.

    The variables GOODH and BADH capture the incidence of an illness in the previous

    periods and the perception of the agent over his health status. It is not surprising that

    individuals who feel ill increase the probability of visiting a doctor while individuals who

    feel that their health status is good are less probably to visit a doctor in the first-stage

    (probit model). This relationship also holds on the second-stage (count data model

    using a negative binomial distribution), this means that the perception of the health

    status is also an indicator for the doctor at the moment of setting the visit schedule for

    the patient.

    There is no evidence that welfare payments (SOZH) have a positive impact over the

    probability of taking the decision to visit a doctor for the first time. However individuals

    who receive welfare payments tend to have more visits to the doctor. As Zweifel

    mentioned, there is an incentive to promote more visits because it generates more

    income to the doctor, in this sense, doctors tend to increase the number of visits of this

    group.

    An important issue revealed by the hurdle model is that income (LOGINC) is not a

    significant variable. Germany has a highly state-financed health-care system like most

    European nations, and subsequently the results obtained in the first stage reveal that asthe cost of medical care is very low citizens with low income does not see the cost as a

    problem at the moment to take the decision to visit a doctor. On the other hand, in this

    kind of systems, the doctors do not know the income level of the patient, furthermore, the

    system gives revenues to the doctor based on the number of patients but not over the

    income of them, in this sense, doctors have no incentive to increase the number of visits

    based on this variable.

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    21212121

    The dummy variables used to measure the differences in labor status showed that the

    reference group (retired or former workers) tends to visit more times a doctor than

    unemployed workers (UNEMP), part-time workers (PT) or full time workers (FT). This

    can be appreciated by the fact that all the dummy coefficients are negatives.

    Seasonal dummies (WINTER, SPRING and FALL) are not significant to explain the

    number of visits to the doctor. However, in the first stage only FALL is statistically

    significant, this means that the probability to visit the doctor for the first time increases in

    FALL over the rest of seasons.

    Finally, it is important to mention that the expected number of visits to the doctor is 3.65

    approximately. This was estimated forecasting the Hurdle model which results are

    shown in the following graphs:

    1

    2

    3

    4

    5

    6

    7

    89

    10

    1000 2000 3000 4000 5000 6000

    DOCTCO_F

    Forecast: DOCTCO_F

    Actual: DOCTCO_Forecast sample: 1 6500 IF DOCTCOD=1

    Included observations: 4075

    Root Mean Squared Error 4.057016

    Mean Absolute Error 2.304492

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    22222222

    0

    100

    200

    300

    400

    500

    600

    700

    800

    900

    2 3 4 5 6 7 8 9

    Series: DOCTCO_FSample 1 6500 IF DOCTCOD=1

    Observations 4075

    Mean 3.654933

    Median 3.084520

    Maximum 9.583826

    Minimum 1.853764

    Std. Dev. 1.631899

    Skewness 1.451277

    Kurtosis 3.947390

    Jarque-Bera 1582.860

    Probability 0.000000

    As we can see, the variables has more concentration over lower values, in this case,

    mean and median are values between 3 and 4 visits which are values near to the

    minimum (approximately 2 visits) while the maximum number of visits is almost 10. This

    is also confirmed by the Jarque-Bera test which is a test statistic for testing whether the

    series is normally distributed (the null hypothesis of a normal distribution), in this sense,

    this test showed that the expected number of visits does not have a normal distribution.

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    23232323

    6. MAIN CONLUSIONS

    The main objective of this work was to understand the determinants of health care

    utilization in Germany and determine if citizen actively involved in sports activities and

    with higher level of education tend to demand more health care services. This objective

    was successfully achieved through the use of specific methods that account for the

    characteristics of our dependent variable.

    On the basis of a Hurdle model using a negative binomial distribution, the determinants

    of the demand for medical services as measured by the number of visits to the doctor in

    the last 3 months was estimated. Moreover, the Hurdle model approach allows us to

    separate and quantify the determinants of medical demand regarding contact and

    frequency decisions. Without repeating all empirical findings, at this point we would like

    to emphasize only the main results:

    For the German case, people actively engage with sports activities are more

    likely to visit the doctor as a first stage decision. This could be explained by the

    fact that this group tend to take care more about their health status. However,there is no evidence that relate this to the number of visits, since this is a medical

    decision which is not involved with the sports activities (second stage).

    Education is a significant variable for both stages, however, for the first stage this

    variable has a positive effect while for the second stage, this variables has a

    negative effect. As a whole, this variable has a positive marginal effect for the

    Hurdle model.

    The expected number of visits to the doctor is approximately 3.65, but the

    distribution of this series showed more concentration over lower values (the

    median is approximately 3 visits) than higher number of visits.

    Finally, it is important to mention that behind this formulation, there are some variables

    not included in the survey that could improve the results for future research and obtain

    even more accurate estimations such as variables related to the illness or the use of

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    private health insurance. Formulations that take into account interdependence between

    demands for health insurance and health care or demand for health specialist (for

    example cardiologists) are also improvements that could be done in the future.

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    7. BIBLIOGRAPHY AND SOURCES

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