,j ..-._.^.
UNITED NATIONS
ECONOMIC AND SOCIAL COUNCIL
Distr.
LIMITED
E/CN.14/POP/155 24 October 1979 Original : ENGLISH
ECONOMIC COMMISSION FO?. /■7T:ICA
Expert Group Meeting on Fertility and Mortality Levels, Patterns and Trends in Africa and
their Policy Implications
Monrovia, 26 November to 1 December 1979
TEE COLLECTIOH OF FERTILITY AND MORTALITY DATA AMONG NOMADS
STATISTICS DIVISICN
ECONOMIC COMMISSION FOR AFRICA ADDIS ABABA
A number of definitions of the term"nomad" have been used in African censuses and surveys-some specific, others rather vague.
An example of a vague definition is the one which defines a nomad as any person belonging to a nomadic household. The more specific defijiitions distinguish between two levels of nomads: pure and ndnrad is definea as any person engaped in rearing livestock and ; roaming about for pasture in doing this, This category never
engages in crop or vegetable faming- If however they engage in crop or vegetable farming periodically, then they are classified as semi-nomads.
In considering methods of collecting fertility and mortality data from pure nomads or semi-nomads (during their migratory period's), it is relevant to review the existing techniques .for enumerating nomads in censuses and surveys in the African region.
A special study, E/.CN. 14/CAS. 10/16 "Study on Special Techniques for Enumerating Nomads in African Censuses and Surveys" has already been published by the Statistics Division of ECA, In the following sections a brief summary of the major techniques is given.
THE ENUMERATION. TECHNIQUES .
Six main methods exist for enumerating nomads: ::
(a) HIERARCHICAL (or social organization) APPROACH:
In this technique, enumeration follows the hierarchical (or feudal) social structure of the nomadic tribe. Assuming that there are four main levels of authority, each nomadic tribe would have a chief, then sub-chief, then under each subr-chief, sub-sub-chief s, and finally at the lowest level under each sub-sub^chief, will be sub-sub-sub-chiefs. Each sub-sub-sub-chief usually maintains a list of heads of households who come under his authority. Ey contacting each sub-sub-sub-chief and making use.of these lists of heads of households, the whole nonadic tribe can be enumerated -
If a nomadic group has this type of social organization and if the various levels of chiefdom would co-operate with the enumerators, then it is possible to enumerate the nomadic households effectively subject to constraints which will nov7 be specified. The major
defects of the method iu ' . hat ths varicuc chlv-:? uo not trust
census or survey officials well enough to give them their "accurate"
lists of heads of households. Even these so-called "accurate.
lists" suffer from the usual defects of list sampling namely, incompleteness, duplication and occasionally inclusion of out of
scope units. Another defect of the method is having assignedenumerators to a sub-sub-sub-chief3 the survey/census organization cannot usually pre-determine the distances to be covered by the enumerators since the nomads roam over a large area. There Is an
instance in a recent census when the enumerators traversed more than 100 miles and nearly entered another country.
(b) WATERPOINT APPROACH
In this method a frame of water-holes is constructed and checked
f completeness. Enumerators are stationed at each water-hole andeach 'person who brings livestock to the water-hole is either
E/CN.14/PGP/155 Page 2
interviewed with respect to the particulars of the other household members or is followed home so that other household members can be interviewed. Another variant cf this method is the areal search around each of the water-points to cover all nomadic tents within close proximity of the water-point. The main advantage of this approach is that given a complete frame of waterpoints, it is simple to implement. There are also variations within the method such as the single day enumeration model which lend themselves to adaption for sampling purposes. The main defects of the method is that a complete frame of water-holes is sel'dom obtained. Secondly, unless the co-operation of the nomads is obtained through an
adequate- communications programme, they tend to shun water-points which can be covered by the enunerator. Also the periodicity of . '. "
watering varies from animal to animal, thus making it necessary
to keep enumerators at waterpoints for considerable periods. In addition, herds are not always sent to waterpoints by members of the households owning them. Thus responses given by such caretakers are not worth much. The possibility of duplications is also quite strong with this technique. In countries like Somalia where water- points can be created by digging along river beds, there is the additional difficulty of maintaining a good record of such water- points .(c) TEE GEOGRAPHICAL OR E.A. APPROACH
This implies dividing f.he nomadic areas into broad geographical units similar to the Enumeration Areas (E.A.) used for the sedentary population. The-estimated population in any such geographical E.A.
is quite small, about 100, The plan is to cover the area in one day, since the nomads ate mobile, The techniques used are similar to those applied in the enumeration of the float ing population in censuses. A reasonable number of enuaerators are sent to each E.A. to ensure completion or enumeration within a short time, say a maximum of eight hours. The main advantage of this technique is that if the nomadic population of the country is not very large and if they are restricted to a small geographical area, it is possible to complete enumeration in a short time, thus minimising the risk of duplication* 'Jhc usual household canvasser approach can be adopted without much difficulty. The principal defect is that it requires the mobilisation of a large force of enumerators
for its successful implementation. If the population of nomads and/or the areas roamed by them,are large then the method is either
impracticable or the cost of achieving satisfactory results is so prohibitive as to render the method an:inadmissible option.(d) GROUP ASSEMBLY METHOD
In this approach, fcije nomads are asked to assemble at a number
of centres (e.g. selected waterpoints) to be counted. They may or
may not be given any inducements to get them to the assigned centres.The main advantage of this technique is that it makes for easy and
quick enumeration. However, it has a major defect. Uhen no incentives are offered, the homads have no motivation for travelling long distance*
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only to be enumerated„ Even where inducements are given there are
no guarantees that they will be sufficiently attractive to get the enumerators to th^ centres- In a pilot survey carried out in one country it was estimated that the discrepancy between the figureobtained by using the group assembly method and the one obtained bv enumerating t'he nomads in -location was 18 per cent approximately.
(e) CAMP APPROACH :
As previously 'explained5 one characteristic feature of nomads is their "nomadism" or migratory movements. But even in this almost incessant mobile state, they pitch camp at various points in their journey. If these camps can be identifieds enumeration can take place there. The advantage of the camp approach is that like the hierarchical methbd there is an identifiable leader who can provide
information on the location of the other households belonging to the camp. But the system has the defect that no comprehensive list, of camps can. ever.be'compiled. Even when such lists can be obtained, they are usually found to be very defective.
(f) SATELLITE IMAGERY:
3y the.use of satellite imagery followed by selected groundwork it is possible to obtain an estimate of the number of nomads. This iu a new technique which is in its pioneering days and has been used raore for ecticating livestock than for counting nomads. If the method were fool-proof it could provide a quick enumeration technique* 'However, tho cost and the rather large margin of
error attached to the technique appears to rule it out at this stage as an effective enui-.erationtool,.There are of o.'ourse other methods vhich have been .used to
enumerate nomads bat f-■■■'■■- ''-.— s~n~ rf rather limited application and will not be considered here,
SAMPLIHG '?0Z Z Z' 2ZZ,IV IKS
In the description ~7 available methods for enumerating nomads,
their advrn'.^--;:. .-; * >. .. . - .— ■■ ^,r, o:.ve;i iiuove, it is easy toIdentify those approaches which can also be applied in sample surveys tc collect data on fertility and mortality. The hierarchical, the camp, the E.A. and waterpoint methods can all be adapted to interview nomads on a sample basis, the order in which the techniques are
given beinr. the order bf preference 'based on degree of difficulty in adaptation. In all four methods, basically a frame exists. If the
frame turns out to be defective,■ then the standard techniques for dealing with defective frames can be-applied* Fowever, the possible sauple designs for each aethod are more complicated, A few examples will suffice to illustrate the point.
In the hierai:ch^c'.Iapnroach, there is a whole spectrum of
admissible sample designs, e.fo5 multi-sta£e, multi-phase and list of sampling. The choice of the design will depend on the usual constrawints ints: cost, precision, , r.-_ .... r?: ir „ eri-ors etCt The point being
made here is that :£ the nomadic population is amenable to enumeration
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Page 4
by the hierachical approach, then it is easy to find an acceptable
design, .
The same comment can be. made with respect to the Enumeration Area Approach, However, there is a limitation to the. types of sampling designs which can usually be used, due to practical
difficulties. In certain circumstances 9 it is advisable to suggest
a complete enumeration of the selected E-A.'s- It cust be notedthat it has been assumed in this discussion that a frame of E.A.'s exist. If estimates of the populations of these E.A.'s exist, these witriielp to improve the estimates of vital rates obtained.
The following illustration of how the camp approach was used,
on a sampling basis in Mauritania is given for illustrative :purposes based on information so far available to EGA since the- final methodological report on the census has not yet been issued.
The Mauritanian population is presumed to consist of two
categories: nomadic and sedentary households. There is a list
of all adults belonging to the various collectivities with the chief of the respective collectivity. This list was the basis of the sampling design. All adults form the universe from which the sample is selected. When a person is selected on a probability basis, information is obtained on the location of his camp and this camp is completely enumerated.
There are three problems with this approach. Firstly,
experience has shown that such lists maintained by chiefs are far from complete. There is also the possibility of out of scope units appearing in the universe. Camps with a large number of adults have a greater probability of being selected than smaller ones.
If these varying probabilities are not taken into account in the estimation procei j, ■ biased estirrntes r.iay be obtained.
Underlying the method applied in Mauritania is of course the
assumption that each camp will have at least one member in one ofthe lists of collectivities maintained, by a chief. If this
assumption proves false, then the first probXo^> of incompleteness mentioned r^.rlier becr:.„;-is :..;i;,: coric^, oiluci. *lioie camps are
omitted from- it -The fourth method ..which is easily amenable to the application of sampling techniques, is the waterpoint approach. Various sampling approaches, have been tried and a sunmary of the main ones will be given below. ; All the three methods described below were developed for use in Somalia. A full account of the techniques is given in the ECA document already referred to.
The first method will for want of a better name be referred to as the 14 day model. A frame of water-holes (or watering points)
was prepared and a 10% stratified random sample selected.Enumerators were stationed at these waterpoints for 14 days. On
the first day, any family sending its livestock to the waterpoint
was enumerated. On the -second day, any family sending its livestockE/CN.14/PCP/1 Page 5
to the waterpoint was enumerated. On the second c'ay, any family sending its livestock was asked where they were on the first day.
If they were at a sample waterpoint and were'not enumerated then they were enumerated. If not,; they were not considered as
falling into the sample and were thus not enumerated and so on.
Families with cattle were not to be enumerated after the tbitd day since it was assumed that cattle would have to be watered at least once every three days, After four days, families owning cattle, sheep or goats should not te enumerated, Others should be asked their whereabouts on the first day. If they were at a sample waterpoint and were not enumerated then they were expected to be enumerated. Otherwise they did not belong to the sample.
This process continued until the fourteenth day when it was assumed that all sample households had been enumerated. The defect in this sample design is obvious and was abandoned in Somalia,
Two substitute models were proposed: the extended period (10 day) and one day enumeration models. In the first model, a screening procedure was administered to identify nomadic house holds from other categories of the population. The Screening questions involved asking questions on farming activities engaged in by the household and the type of livestock watered by them.
If for example the type of livestock reared by the household was cattle, "then the interview was terminated in the first day. But
if no cattle were reared but sheep and goats in addition to camels
were reared then the interview was also terminated. 'But if only camels were reared then the interview continued. This screening process was continued from the second to the tenth day. On thebasis of the results obtained it was possible to put the sample households coming to the waterpoints from nomadic or semi-nomadic into three mutually exclusive groups. These groups ijere; (a) households with cattle with or without other livestock; (t) house holds wit-h sheep and goats with no cattle but wi-tV or without camels;
and (c) households with camels only. A screening process, was
also adopted to ens'ure that there was no duplication. However, as thii's screening process involved asking the respondent whether hebeen to any of the water points to water aninals during the days, it was obvious that it was not a full-proof method.
it should be pointed out that nomads are normally on the move and unless a great deal of publicity has been made about the
objectives of the survey and great rapport has been built up between the enumerators and the nomads they would tend to avoid water-
points to which enumerators had been assigned unless they have no choice. This, therefore, would tend to bias the results of the survey. The assumption underlining the 10 day model is that within 10 days almost every type of livestock would have been to a watering point. The ronly possible exception being a few camels and the
number would not seriously affect the results of the survey and for this small number of camels a de-bia.sing procedure can be adopted.
It was likely that even if the 10-day model was completely full-proof it would expose the interviewers to serious problems such as being stationed in very hot and arid conditions for a
E/CN.U/POP/155 Page 6
period of 10 days, A substitute model known as a one-day model was therefore proposed. The screening process was the same as
for the 10-day model with an additional question on how many days ago were these animals watered. "On the surface this model appears very simple but conceptual and organizational problems associated with its application are great and in the case of Somalia the method was not adopted in the census. It is worth mentioning that in the actual census operation a modified form of the 10-day model, namely a 14-day model was adopted.
GENERAL RECOMMENDATIONS OH THE APPROACH TO SAMFLING NOMADS We have in the previous sections reviewed the basic tech niques which have been used in censuses and surveys to enumerate nomads and which are likely to prove amenable to the collection of fertility and mortality data. However, it is necessary to point out that a great deal of testing and field studies still need to
be done in individual countries before a particular method can be set to be the most suitable for that country. All the method reviewed earlier have advantages but also serious defects and before a
country decides oil which method to adopt, it has to take into
account the process of advising many professionals in its estimates at given costs and in this case- we are not referring only to the sampling 'error but to the total error of the design, namely
sampling error, coverage error and content error, THE BASIC FERTILITY AND MORTALITY QUESTIONS
It is obvious from the in enumerating nomads that the World Fertility Survey application to the enuinerat are administered on a very in a position to mingle and appro-ach, therefore, would questionnaire which can be The following list is given
Age Sex
description of the difficulties inherent questions of the type administered in , are not likely to prove suitable for ion of nomads unless, of course, they snail sample and the interviewers are
move with the nomads. The usual be the design of a relatively short administered quickly to each household.
for illustrative purposes only:
Relationship to head of household Paternal orphanhood
Maternal orphanhood . . ■ ■■
No. of live births and . . .
particulars of recent live births (for women aged. 15 years or more)
Births in household during past 24 months and
deaths in household during past 24 months (for heads of households only).
OTHER METHODS OF OBTAINING INFORMATION FROM ADMINISTRATIVE RECORDS Obtaining vital rates from civil registration records in most
F/CN.14/POP/155 Page 7
of Africa even among the sedentary population is c. " \ •: f icult
task. It vjould prove even more of a problem to try to obtain the information from the nomadic population. The only possibility at present would be a nomadic population with a well defined
social or administrative structure. The civil registration system could then be built into the form of imperfect population registers now maintained by such nomadic groups. However, even if such a possibility existed,it would be sometime yet before these records could be utilized to derive reliable vital rates,
CONCLUSION
A lot of work still remains to be done to evolve the most efficient methodology for enumerating nomads in African countries.
In some of the surveys carried out in Africa, the nomadic areas of the countries have been ignored because of the difficulty
of evolving such a methodology and the cost of covering the nomads using existing methods. The Regional Censuses and Surveys Advisory
Service in EC A has ^t,ar,ted being operational and some of these V
problems will be Hutfown. In the meantime countries would have
to examine the methods which have been used in the censuses and see whether they can be adapted for use in surveys.
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