THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
PROSPECTIVES FOR GROWTH : A SYSTEM DYNAMICS STUDY OF THE ROMAN
CATHOLIC PRIEST POPULATION OF THE NETHERLANDS
Oostveen J.P.* and Sweeny D.J.*
Abstract
Sponsored by a Dutch Roman Catholic Foundation a System Dynamics computer
simulation model has been developed to study the population dynamics of
priests of the Dutch Roman Catholic Church,
Few vocations since the second half of the sixties led to a disproportional
"going grey! of the priest population, This is manifested not only in the
unbalanced age structure but also ina relatively high number of retire-
ments.
The model (see enclosed flow diagram) structures on the one hand the physi-
cal demographic processes and on the other embodies a theory based on
observation of qualitative aspects of disaggregated priest, believer and
non-believer populations. Church attendence figures for instance are used
as a measure of vocation potential.
The model is used to articulate the insights on the influence of policy
alternatives on priest population in the coming 50 years or so.
* Department of Civil Engineering, Delft University of Technology, The
Netherlands.
1.183
1.184 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
HISTORICAL INTRODUCTION
The paper discribes work done on a System Dynamics Study for a private
foundation interested in providing information and documentation concerning
the Roman Catholic Church in Holland, One of the problems coming into view
was the drastically reducing numbers of priests available to man the paris-
hes, the basic organisational unit within the Roman Catholic Church,
Figure 1 (Qostveen 1986) shows how dramatic the problem is for the Church
and her faithfull parishoners.
a rt -ordinations
8 tt a left office
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2 Vy
a I
g.au3
a
o? bt
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ee eed
a
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re a ee re
$88 time ‘Cyears)
Figure 1: Dramatic decline in ordinations
Figure 2 (Oostveen 1986) shows what this means in terms of absolute num-
bers of priests available in comparison with the Roman Catholic population,
Although this population has been even declining a little recently the
relation between numbers of pastors and faithful is well below standard,
Whereas in 1965 for instance the roughly 2000 parishes in The Netherlands
had 2 priests on the average, at the moment quite a few parishes cannot
even have one,
THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
population (x 1,000,000)
priest population (x 1,@00)
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Figure 2:
Priest population compared with total R.C. Population
1.185
1.186 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
Prognoses by the Catholic Statistics Bureau KASKI (1985) suggest that if
the present trend continues in the year 1990 only 1900 priests will be
available for parishes against 4092 in 1965.
The main reason is of course the graying priest population, as shown in
table 1.
Age group Numbers _ Percentage
1.1.83 (KASKI 1985)
25-34 64 21
35-39 140 4h
40-54 1305 4a
55 and older 1641 = 52.1
Total 3150 100,0
Table 1: Age structure priest population
With more than half of the population 55 years or older, unless there is
an equivalent recruitment rate, within 10 to 15 years the population will
have practically been halved. And recruitment rate is extremely low.
REBELLIAN AGAINST THE SEEMINGLY INEVITIBLE
The Catholics of Holland are however a staunch race. Their history during
and since the Reformation proves they. will not easily succumb to the seem-
ingly inevitible. Without legal rights after about 1573 and virtually
forbidden to have priests they developed systems of importing missiona~
ries from other lands and sending their youth to seminaries abroad so that
great numbers succeeded in keeping their faith and traditions alive (Rogier
1945).
A second feature of this rebelliousness is the fact that very often laymen
and not clerics took a major part in bringing about change. A famous
example was the fight for Catholic emancipation during the first half of
the 19th century. Some of the more important newspapers were initiated by
Catholic laymen (Nieuwe Rotterdamse Courant, Handelsblad, De Tijd) and
singular was the memorandum of J.A. Alberdingk Thym in 1852, bye-passing
all official (clerical and Government) channels convicing Pope Pius IX to
reinstate the dioceses of Utrecht and Haarlem on the grounds that tradition
demanded it as Utrecht was the bishop's chair of Willibrordus in the 8th
century.
So the question posed by the Roman Catholic (lay) client was: what is to be
dame about this decline, What are the possibilities for growth anew?
In fact, leaving aside the religious convictions involved, this is just the
reaction of the businessman who sees his business going down, He is con-
vinced his product is good and asks himself where have I been slipping-up
in management. He calls in his advisors and tries to analyse the situation
before taking decisions based on facts but also on his strong intuition and
especially, convictions.
The question asked of the modelling effort can be represented by figure 3.
In 1¥00 INFEKNATIUNAL GUNFERENGE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986. 1.187
Ll
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3
ol
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2 2
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S 4
a 44
& T T rar EE oi
a ee ee
3 8 time (years)
Figure 3: How will the priest population develope?
As this is basicly a demographic system with management policy interactions
the System Dynamics Method (Forrester 1963, Pugh 1982) seemed a very
suitable quantifying and presentational approach.
1.188 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
BASIC ARGUMENT OF THE MODEL
Figure 4 shows the basic hypothesis underlaying the behaviour of the sys—
tem. As is clear from the above it is based on strong convictions, rooted
in historical experience.
Desired
Priests
per Laity
Desired
Priests
Quality
Lintex
Priests
Needed
Qualitative
F of
Nuaber of
Priests
Vocation Index
of bait
POLICY
Priest oriented Diaconate ay oriented
4 Vocation Pastorate # Youth Pastorate
t Priest Studies 4 Fanily Pastorate
1 Priest Care 4 Adult Pastorate
# Priest Migration
Figure 4: Basic argument of the priest population behavioural model
INE 1900 INTERINATIUNAL CUNFERENUE UF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986, 1.1659
BASIC MODEL STRUCTURE AXTICULATED
The model includes three demographical streams: priests, lay catholics
and non-catholics, See figure 5.
7 gration =, Za Leaving
RY
+ + + + na
oS a —/s Zarit
Priest Priest Diacon Diacons frigsts (=) everiti
Vocation + Students Ordination Ordination - -
Noraal Musber Priest Study Duration as Priests average
of Laity per Duration Diacon Needed Office Tere
Vocation es) ES
policy: Desired Nunber of
ft Vocation Pastorate, Laity per Priest
4 Priest Studies.
t Priests Cares.
t Priests Migration.
+ Youth Pastorate,
t Fasily and Adult Pastorate.
+
ao. ma,
Birth, (tie ae Heaths
ei
= Lif
Average Non_baptise: ce Conversion Average Life
Naber Expectancy
of Birth Drop_out
i +
‘Y ie ~a y-
Birth, (+) thers. (=) Deaths.
ie ee
Figure 5: Priest population influence diagram
The priest "stream" begins with vocations to the priesthood, continues
through an average of 5 years philosophical and theological studies and
spiritual and pastoral formation followed by ordination first as deacons
followed after about one year by ordination as priest at about the age of
25 years, Priests continue for life, though they become pensioned (emiri-
tus) from fulltime pastoral activities usually at the age of 65 to 70
years.
1.190 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986,
The lay Catholic "stream" starts at birth, or rather baptism into the
Church, and continues normally for life.
The non-catholic "stream" is the difference between total population of the
Netherlands and the priest and lay Catholic populations,
Influencing these "physical" conservative systems or streams are various
policy factors, Indicated in figure 5 are
1) Vocations pastorate which aims at creating the right conditions for
fostering young men to follow the spriritual call to the priesthood. It
includes for instance building up the image of the priest as some one with
a special, important and (spiritually) rewarding task in life.
2) The quality of preparation of the priests for their task is obviously
very important for the growth of many aspects of the Church. One can
compare it to the quality of training for executive and management posts in
business.
3) It is of course not enough to provide a ‘once and for all' education,
training and formation, As in other fields of knowledge and work the people
involved must be more or less continually kept up-to-date: you could call
it ‘education permanent’,
4) It is obvious that the young generations have to be well cared for if
their knowledge and living of the faith is to grow. Youth pastorate is
intended to look to this.
5) The family and adults have their own pastoral needs. Many church pro-
grams of pastoral activity are specifically directed towards these groups,
How the ‘physical’ streams relate to the "policy" factors is more explicit-
ly shown in Figure 6, where the three main streams are further disaggre-
gated into age classes, and more importantly, quality classes,
1.194
INE 1960 INTERKNATIUNAL GUNFEHENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
rn
CN
Bait
The disaggregated priest population flow diagram
Figure 6
1.192 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
HOW QUANTIFY QUALITY DIFFERENCES?
It was quite obvious that a good deal of the problem of few vocations,
recruitment rate and ensueing 'graying' of te priest population was a
crisis of identity. For various reasons which we cannot go into here but
which are abundantly documented elsewhere (Bots 1982, Van Munster 1982),
many lay catholics together with their priests had been losing a sense of
mission and were little by little being engulfed in a more and more secular
society, which was forgetting the judeo-christian origins of its more
fundamental values.
This required the definition of quality indices for both lay and priest
populations.
The suitable index of quality for the. catholic lay population was found in
church attendance rates, The technical report (Qostveen 1986) on this work
provides more detail on this point but fig. 7 shows the relevant hostorical
trends.
we
+} KASKI 7 ur and over
eve NIPO 1@ yr and over
esa 0BS 18 / 25 ur
1
2. 25 / 45 ur
3.
22-2 IO . 45 yr and over
of the R.C. population
.
%
vse +
time Cyears) z
Figure 7: Church attendance per age group, year 1960 through 1985
Based on these trends the lay population age groups were initialised with
qualities expressed as percentages of desired quality:
0-20 years “15
20-45 years a5
45 years and older 55
In the case of priests, quantification of quality was much more difficult,
One relevant factor however was the number of vocations. From historical
sources and expert advice it was possible to determine average incidence of
vocations in what one might call a healthy thriving spiritual community
that the church ought to be,
Indentification of potential candidates with attractive images of what a
priest is and does is by far the greatest influencing factor in promoting
vocations. The quality of the priest determines the number of vocations
(and also to some extent the quality). A simular mechanism is true in
general in all walks of life, so we found this a plausible approach to
filling-in an initial quality for the priest population,
I HE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986. 1.193
It is assumed that on the average every priest during his active lifetime
is able to inspire his church members in such a way that at least 3 vocat-
ions arise.
This means for a priest population of about 3800 in 1977-78 in 1983-84
about 170 ordinations might be expected. In fact there were only 26, so
that the model is initialised with a quality index of 26:170 = 0,15,
MODEL STRUCTURE
Having decided to dissagregate the priest and lay catholic population not
only according to age but also according to quality it was necessary to
consider the relationship between the formal (total) populations and the
equivalent or quality population of practising (i.e. regularly church
going) catholics and the 'quality' population of priests(i.e. equivalent
number of priests able to inspire potential vocations).
The main features of these relations can be followed in Figure 6.
Thestream of non-catholics
This is determined on the one hand by its size and the stream entering and
leaving. It is divided into three age groups: 0-20, 20-45, and 45 and
older, the stream form one to the other depending on the duration in each
group. The stream entering comes from births, both those from own populat-
ion and those from children born to catholics but not baptised, The number
of births is taken to be the number-of women in the 20-45 year group
devided by the duration in this group multiplied by the average birthrate
somewhat adjusted to llow for the 3% births to women outside this: group.
The birth rate assumed is 1.5, see Figure 8
The average death rate is determined by dividing the 45 and older popula~
tion by the average lifetime of this group which is for the Netherlands the
average life expectancy of 78.5 years minus 45 = 33.5 years.
Besides this the population can change through conversion and/or lapsing,
bea
fertility
<<
Pf
ie
1
3 time Cyears) 8
Figure 8: Average number of children to women aged 20-45 yrs.,
1950 to 1985
1.194 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
Both the number of not baptised children born to catholics and the result
of conversion and lapsing (negative conversion) is highly dependent on the
quality index of the catholic population,
This is explained further in relation to the stream of catholics.
The stream of catholics
This stream consists of the formal population of all registered catholics
and a subset of the practising catholics. A quality index gives the rela—
tionship between the formal and the subset population, As already discussed
the index is based on the National Bureau of Statistics figures for church
attendance.
The age groups are the same as for non-catholics.
The birth in-stream for the formal population is that given by the normal
birthrate less those not baptised.
The number baptised is taken to be influences by the quality index (Figure
10 a
9). —
‘
oO —
5
:
:
:
§
Se
:
3k
a8
ea
53
83
28
é
B%
E
i Os 10
quality index 20 /45 years
Figure 9: Influence of quality index on baptisms
The birth in-stream for the practising population is determined by the
number of baptisms and these are assumed equal in this case to the number
of births, Because of religiosity (expressed as church attendance) stat-
istics show that a higher birthrate can be taken for believers (V.d.Giezen
1985), The quality index is again taken to influence this so that a lower
index gives a birthrate equal to the rest of the population (Figure 10).The
maximum is taken to be that from before 1960 which was roughly 3 (Figure
8). P
8
By
oO
a
o 2
Bo
fe
Bo:
«$
fa
Bas
He
as
° r T T T t T
mT af 1
quality index 20 / 45 years
Figure 10: Influence of quality index for 20-45 year age group on birthrate
Tht 1Y8b INIEKNAITUNAL GUNFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986. 1.195
The connection between the formal and practicing population is dependent on
the relevant quality indices and also Church policy programmes such as
religious instruction and youth and adult pastoral activities. This connec-
tion is seen in the model as in and out stream to and from the practising
subset of population. The direction of the stream is dependent on the value
of the influencing quality compared with that of the formal population, The
value of the stream is a function of the population and a streamfactor,
Depending on the quality index value, positive or nagative, a certain
percentage streams in the one or other direction, Figure 11 shows the
relationship used.
vhs oo
difference in quality index
streamfactor
Figure 11: Stream factor between formal and practicing population
‘This stream factor is used in principle throughout the model, The different
interacting variables are attained by weighting this factor.
The main influences considered are:
* Influencing the 0-20 yrs group.
= Quality of the 20-45 yrs group where the families are formed and the
children grow up. The influence is large. A weighting factor of 2 is taken,
= Quality of the 45 yr and older group. The influence of grandparents and
adults on children is evident but less than the home, We take a weighting
of 1.
~ Quality of priests. They represent not only the Church, but religion
itself. This influence on the young is paramount. Weighting 3.
- Quality of youth pastorate.Here religious instruction and living are
central, Both the quality of the instruction (influenced by priest quality)
and instruction policy quality (Hierarchy) are involved, Weight is taken as
the average of priest quality and policy factor with its own weight valued
at 3, In the zero-alternative (no policy changes) the policy factor is
taken as the initial value of the quality index of the priest population,
* Influencing the 20-45 yr. group.
~ Quality of the two other groups. A weight of 1 is taken,
~ Quality of priests. Very important for families and young adults.
Weight 2.
= Quality of family and adult pastoral activities, On these depend con-
tact with means of growing in the community, Weight factor 2,
1.196 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986,
* Influencing 45 yr and older group.
= Prosumably influences from the other two groups but not weighty: 1.
~ Quality of priests. Mature adults will be less influenced, Weight 1.
The priest stream
From Figures 5 and 6 and what has already been said the general structure
of the priest stream will be clear. Here again the stream is divided into a
formal part and a subset indicating quality differences.
Average vocations are determined from the potential number of youths from
which vocations can come and an average number of vocations per number of
youths. The potential number of youths from which vocations can reasonably
be expected is determined by multiplaying the formal number of youths by
the relevant quality index.
The average number of youths to a vocation is assumed determined by the
product of a norm value and a number of influencing factors thus incorpora~
ting sociological and policy influences on vocations in the model.
The more important influences brought into the model in this way are:
~ Influence of average number of children, Practice has shown that relat-
ively more vocations came from large families;
- The need for priests will influence the selection criteria;
- Influence of vocation policy programmes.
The levels in the priest stream are also influenced by the rates of failure
in studies (40%), the internal rates of change from formal to quality
subset and also migration,
The internal change from and to the priests subset of population and formal
population is similar to that described in the case of the catholic lay
population. It depends on the quality indices, The main influences are:
= the quality of the lay faitful: weight 1;
~- the quality of priests (on students): weight 2;
- the quality of education of students: weight 3;
~ policy with regards to looking after, and continual education of the
priests.
POLICY ALTERNATIVES.
The normal policy alternatives have already been named:
- Family and adult pastoral programmes
~ Youth pastoral programme
- Vocations programme
~ Priest education programme
- Care for priests in service,
Another extra policy alternative is immigration of priests (or priest
students) from elsewhere. In fact this has been going on for a number of
years now. Dutch missionaries have been repatriated and have been able to
£ill a gap in the ranks of the priest population. But this possibility is
drying up so that further migration would have to come from other coun-
tries.
In the model the normal policy alternatives are assumed possible with 80%
effectiveness reduced only by the quality index of the priest population as
this is also the main instrumental influence in carrying out the various
IME 1986 INIEHNAIIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986. 1.197
programmes, The better the priest population the more effective the pro-
grammes.
In the case of migration, tests are run with the migration of maximum 25
and maximum 50 priests per year with a delay time of 3 years,
RESULTS
The following alternatives were run and results are summarized in figure 12,
2
>
a
» 2
historical |simulated_ can
id Pian to
oa
be
43
ae
5
priest population Cx 1,000)
a a a ee ae ee a
8 time (years) 8
wing the priest population in time as a
50
0
Figure 12: Simulation results shor
result of various policies
Figure 13 shows that the model total population compares satisfactorily
with National Bureau of Statistics (CBS)forecasts in three variants,
1.198 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
¥ historical | simulated
®
a4 forecast CBS: >
3 I low variant 2
8a I middel variant a
| TI high variant co
8 Ba
8 ge
= om oc
x as
: “
5 «4 i
3 e
Ss
3
a
B 14
fo
8
a]
2-4
4
° T T as
rr a ae ee a ee
& S time (years? §
Figure 13: Model total population forecast compared with CBS
forecasts
The policies and results are as follows:
Zero-alternative: This is the case when no action is taken, Even this shows
a more optimistic result than the KASKI forecast (Hemert 1985 and figure
12).
Zero-pius-alternative: This shows the effect of including an increased
fertility rate due to increased church-going rates. Only after ca, 25 years
does this begin to make a difference,
This alternative is included in all the following.
Youth, family and adult programmms (alternative 1).
In the end these programmes help in counteracting decline but only on a
longterm basis do the results begin to be effective in terms of more
priests,
Vocation and priest care programmes (alternatives 2).
These programmes alone double the results in time compared with programmes
directed only at the lay people.
Programmes directed at both lay and priest populations (combination of
alternatives 1 and 2),
Give even better results in time but it still takes about 50 years to
reach even the 1984 level of priest numbers.
Immigration of priests (alternatives 4 and 5).
This together with programmes on all fronts is to only way to really get
THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986. 1.199
things done in a relatively short time. Even then it will take about 25
years to get back to even 1984 standards that are seen as being less than
ideal.
CONCLUDING REMARKS
One of the main results of the model was the demonstration (even to the
sponsoring body) that the natural time-lag inherent in such a demographic
system made it practically impossible to bring about major changes in less
than 50 years counting on normal local resources.
Only by making abundant use of external resources through immigration is it
probable that the level of population of priests existing at this moment
(1986) can be regained. The consequence is inevitable decline if not extin-
ction or strong and bold measures on all fronts, including necessarily
abundant immigration of priests from elsewhere,
This last is far from unrealistic as various countries such as Poland can
probably supply the right men, and the missionary experience of the Church
in The Netherlands is such that the associated inculturization problems
need not influence the policy unduely,
Qperationalizing the immigration policy and indeed the other policies has
not been the subject of this study, As is the case with (missionary)
inigration the Dutch Catholic church has also very much experience and
spiritual heritage in all sorts of pastoral entrepreneurship. This model is
simply a sophisticated way of confirming the popular truth "where there's a
will, there's a way",
1.200 THE 1986 INTERNATIONAL CONFERENCE OF THE SYSTEM DINAMICS SOCIETY. SEVILLA, OCTOBER, 1986.
REFERENCES
Bots, J., 1981. 60 years Catholicism in the Netherlands. De Rots. Venlo
(Dutch).
Forrester, J.W., 1961. Industrial Dynamics, Cambridge, MIT Press,
Giezen, G.J., v.d., 1985. Social norms regarding family size. Monthly
population statistics, CBS 85/9, (Dutch)
Hemert, H.M.J., 1985, Trends in active priest population in The
Netherlands, KASKI, 14-3-1985 (Dutch).
KASKI (1985), Main figures from Church Statistics of the R.C. Church Pro~
vince in The Netherlands, edition 1975 through 1984, various memoranda (in
Dutch).
Munster, H.A, van, o.f.m., 1982, Collected lectures, Secretariate of the
RC, Church Province, Utrecht, 1982.
Oostveen, J.P., 1986, A Dynamic Personnel Policy. A Simulation Model for
studying the development in time of the R.C. priest population in The
Netherlands. Department of Civil Engineering, Delft University of Techno-
logy Delft. (In Dutch)
Pugh, A.L. ILI, (1976). DYNAMO User's Manual, Sth ed. The MIT Press,
Cambridge, Massachusetts.
Rogier, L.J., 1945. Short History of the Roman Catholic Church in The
Netherlands. Urbi et Orbi, Amsterdam (In Dutch),
CC BY-NC-SA 4.0