A THEORY OF MIGRATION It was a remark of Farr's to the effect that migration appeared to go on withoutany definite law that led Ravenstein to present his celebrated paper on the laws of m
igration before the Royal Statistical Society on March 17, 1885. This paper was based upon the British Census of1881, but in 1889 Ravenstein returned to the subject with data from more than twenty countries.Finding corroboration for his earlier views in this broader investigation, he also entitled his second paper, "The Laws of Migration," though he noted that it was ambitiously headed and warned that "laws of population, and economic laws generally, have not the rigidity of physical laws." An irreverent critic,Mr. K.A. Humphreys, immediately retorted that "After carefully reading Mr.Ravenstein's former paper, and listening tothe present one, [I arrived] at the conclusion that migration was rather distinguished for its lawlessness than for havingany definite law.Mr. Stephen Bourne'scriticism was less devastating but logically more serious: "that although Mr. Ravenstein had spoken of 'Laws of Migration,'he had not formulated then in such acategorical order that they could be criticized.”Nevertheless,
Ravenstein's papers have stood the test of time and remain the starting point for work in migration theory. As found in the first paper and extendedor amended in the second, Ravenstein'slaws are summarized in his own words below. The first five
of these items includethe laws as they are usually quoted, while items 6 and 7, though taken from the general conclusions of his second paper, arenot ordinarily included. This, however, is due more to Ravenstein's way of numbering the laws and to his somewhat tentative statement of the dominance of the economic motive than to his own estimateof the importance of his conclusions.
* Presented at the Annual Meeting of theMississippi Valley Historical Association, Kansas City, April 23, 1965 (“Population Studies CenterSeries in Studies of Human Resources," No. 1). This paper has benefited greatly from discussionswith Professor Surinder K. Mehta. E. G. Ravenstein, "The Laws of Migration,"Journal of the Royal Statistical Society, XLVIII, Part 2 (June, 1885), 167-227. Also Reprint No.S-482 in the "Bobbs-Merrill Series in the Social Sciences." Ravenstein, “The Lam of Migration," Journal of the Royal Statistical Society, LII (June, 1889), 241-301. Also Reprint No. S-483 in the"Bobbs-Merrill Series in the Social Sciences."
3 ('Discussion on Lfr. Ravenstein'sPaper,"Journal of the Royal Statistical Society, LII (June,1889),302
1. Migration and distance.-(a)"[T]hegreat body of our migrants only proceed ashort distance" and "migrants enumerated ina certain center of absorption -will . . . growless [as distance from the center increases]"(I, pp. 198-99). (b) "Migrants proceeding long distancesgenerally go by preference to one of the greatcenters of commerce and industry” (I, p. 199). 2. Migration by stages.-(a)"[T]here takesplace consequently a universal shifting ordisplacement of the population, which produces 'currents of migration,' setting in thedirection of the great centers of commerce andindustry which absorb the migrants" (I, p.198). (b) "The inhabitants of the country immediately surrounding a ton= of rapid growthflock into it; the gaps thus left in the ruralpopulation are filled up by migrants from moreremote districts, until the attractive force ofone of our rapidly growing cities makes itsinfluence felt, step by step,to the most remotecorner of the kingdom" (I, p. 199). (c) "The process of dispersion is the inverseof that of absorption, and exhibits similarfeatures" (I, p. 199). 3. Stream and counterstream.-"Each maincurrent of migration produces a compensatingcounter-current" (I, p. 199). In modern
terminology, stream and counterstream havebeensubstituted for Ravenstein's current andcounter-current. 4. Urban-rural differences in propensity tomigrate.-"Thenatives of towns are less migratory than those of the rural parts of thecountry" (I, p. 199). 5. Predominance of to females among among short-distance short-journey
migrants.-"Femalesappear migrants" (II,p. 288).
6. Tech~zology and n1igration.-['Doesmigration increase? I believe so! . . . WhereverI was able to make a comparison I found thatan increase in the means of locomotion and adevelopment of manufactures and commercehave led to an increase of migration" (11, p.288). 7. Dominance of the economic motive.-"Bador oppressive laws, heavy taxation, an unattractive climate, uncongenial social surroundings, and even compulsion (slave trade, transportation), all have produced and are stillproducing currents of migration, but none ofthese currents can compare in volumewiththat which arises from the desire inherent inmost men to 'better' themselves in materialrespects" (11,p. 286). This century has brought no comparable excursion into migration theory.With the development of equilibrium analysis, economists abandoned the studyof population, and most sociologists andhistorians are reluctant to deal with masses of statistical data. A crew of
demographers has sprung up, but they havebeen largely content with empirical findings and unwilling to generalize. Indeed,Vance, in his presidential address to thePopulation Association of America, entitled "Is Theory for Demographers?"contends that demography, for lack oftheory, remains unstructured and raisesthe question, "Is there room [in demography] for the bold and audacious?" In the three-quarters of a centurywhich have passed, Ravenstein has beenmuch quoted and occasionally challenged.But, while there have been literally thousands of migration studies in the meantime, few additional generalizations havebeen advanced. True, there have beenstudies of age and migration, sex and migration, race and migration, distance andmigration, education and migration, thelabor force and migration, and so forth;but most studies which focused upon thecharacteristics of migrants have been conducted with little reference to the volumeof migration, and few studies have considered the reasons for migration or the assimilation of the migrant at destination.So little developed was the field in the1930's that Dorothy Thomas and her associates concluded that the only generalization that could be made in regard to differentials in internal migration was that migrants tended to be young adults orpersons in their late teens.Later Bogueand Hagood trenchantly summed up thecurrent state of knowledge under theheading "An Approach to a Theory ofDifferential Migration,"and Otis
DurantDuncan contributed a valuable essay on"The Theory and Consequences of Mobility of Farm Population,"~ but bothwere restricted to the United States andboth were hampered by a lack of datawhich has since been partially repaired.Most essays in migration theory havedealt with migration and distance and advance mathematical formulations of therelationship. Perhaps the best known ofrecent theories of migration is Stouffer'stheory of intervening opportunities. Except for Dudley Kirk,Ravensteinseems to have been the last person tomake a detailed comparison of the volumeof internal migration or the characteristicsof migrants within a goodly number of nations. Generally speaking, considerationsof internal migration have been divorcedfrom considerations of immigration andemigration, and very short moves, such asthose within counties in the United Statesor within Kreise in Germany, have notbeen considered along with the longer distance movement that is labeled migration.Also, such forced migration as the refugeemovements of World War II and its aftermath have not been grouped with the so-called free migration.It is the purpose of this paper to attempt the development of a generalschema into which a variety of spatialmovements can be placed and, from asmall number of what would seem to beself-evident propositions, to deduce anumber of conclusions with regard to thevolume of migration, the development ofstreams and counterstreams, and the characteristics of migrants. As a
starting pointfor this analysis, a definition of migrationis introduced which is considerably moregeneral than that usually applied. DEFINITION OF MIGRATION Migration is defined broadly as a permanent or semipermanent change of residence. No restriction is placed upon thedistance of the move or upon the voluntary or involuntary nature of the act, andno distinction is made between externaland internal migration. Thus, a moveacross the hall from one apartment to another is counted as just as much an act ofmigration as a move from Bombay, India,to Cedar Rapids, Iowa, though, of course,the initiation and consequences of suchmoves are vastly different. However, notall kinds of spatial mobility are includedin this definition. Excluded, for example,are the continual movements of nomadsand migratory workers, for whom there isno long-term residence, and temporarymoves like those to the mountains for thesummer. No matter how short or how long, howeasy or how difficult, every act of migration involves an origin, a destination, andan intervening set of obstacles. Among theset of intervening obstacles, we includethe distance of the move as one that isalways present. FACTORS IN THE ACT OF MIGRATION The factors which enter into the decision to migrate and the process of migration may be summarized under four headings, as follows:1.
Factors associated with the area of origin.2. Factors associated with the area of destination.3. Intervening obstacles.4. Personal factors. The first three of these are indicatedschematically in Chart 1. In every areathere are countless factors which act tohold people within the area or attractpeople to it, and there are others whichtend to repel them. These are shown in thediagram as + and - signs. There areothers, shown as 0's, to which people areessentially indifferent. Some of these factors affect most people in much the sameway, while others affect different people indifferent ways. Thus a good climate is attractive and a bad climate is repulsive tonearly everyone; but a good school system may be counted as a + by a parentwith young children and a - by a house-owner with no children because of the highreal estate taxes engendered, while anunmarried male without taxable propertyis indifferent to the situation. Clearly the set of +'s and -'s at bothorigin and destination is differently defined for every migrant or prospective migrant. Nevertheless, we may distinguishclasses of people who react in similarfashion to the same genera1 sets of factorsat origin and destination. Indeed, since wecan never specify the exact set of factorswhich impels of prohibits migration for agiven person, we can, in general, only setforth a few which seem of special importance and note the general or average re-action of a considerable group. Needlessto say, the factors that hold and attract
orrepel people are precisely understoodneither by the social scientist nor the persons directly affected. Like Bentham'scalculus of pleasure and pain, the calculusof +'s and -'s at origin and destinationis always inexact. There are, however, important differences between the factors associated withthe area of origin and those associatedwith the area of destination. Persons living in an area have an immediate andoften long-term acquaintance with thearea and are usually able to make considered and unhurried judgments regardingthem. This is not necessarily true of thefactors associated with the area of destination. Knowledge of the area of destinationis seldom exact, and indeed some of theadvantages and disadvantages of an areacan only be perceived by living there.Thus there is always an element of ignorance or even mystery about the area ofdestination, and there must always besome uncertainty with regard to the reception of a migrant in a new area. Another im~ortant difference betweenthe factors associated with area of originand area of destination is related to stagesof the life cycle. For many migrants thearea of origin is that in which the formative years have been spent and for whichthe general good health of youth and theabsence of annoying responsibilities createin retromect an overevaluation of thepositive iements in the environment andan underevaluation of the negative elements. On the other hand. the difficultiesassociated with assimilation in a new environment may create
in the newly arrived a contrary but equally erroneousevaluation of the positive and negativefactors at destination. While migration may result from acomparison of factors at origin and destination, a simple calculus of +'s and -'sdoes not decide the act of migration. Thebalance in favor of the move must beenough to overcome the natural inertiawhich always exists. Furthermore, between every two points there stands a setof intervening obstacles which may beslight in some instances and insurmountable in others. The most studied of theseobstacles is distance, which, while ornnipresent, is by no means the most important. Actual physical barriers like theBerlin Wall may be interposed, or immigration laws may restrict the movement.Different people are, of course, affected indifferent ways by the same set of obstacles. What may be trivial to somepeople-thecost of transporting house-hold goods, for example-maybe prohibitive to others. The effect of a given set of obstacles depends also upon the impedimenta withwhich the migrant is encumbered. Forsome migrants these are relatively unimportant and the difficulty of surmountingthe intervening obstacles is consequentlyminimal; but for others, making the samemove, the impedimenta, among which wemust reckon children and other dependents, greatly increase the difficulties posedby intervening obstacles. Finally, there are many personal factors which affect individual
thresholdsand facilitate or retard migration. Some ofthese are more or less constant throughoutthe life of the individual, while others areassociated with stages in the life cycle andin particular with the sharp breaks thatdenote passage from one stage to another. In this connection, we must note that itis not so much the actual factors at originand destination as the perception of thesefactors which results in migration. Personal sensitivities, intelligence, and awareness of conditions elsewhere enter into theevaluation of the situation at origin, andknowledge of the situation at destinationdepends upon personal contacts or uponsources of information which are not universally available. In addition, there arepersonalities which are resistant to change-changeof residence as well as otherchanges-and there are personalities whichwelcome change for the sake of change.For some individuals, there must be compelling reasons for migration, while forothers little provocation or promise suffices. The decision to migrate, therefore, isnever completely rational, and for somepersons the rational component is muchless than the irrational. We must expect,therefore, to find many exceptions to ourgeneralizations since transient emotions,mental disorder, and accidental occurrences account for a considerable propor-tion of the total migrations. Indeed, not all persons who migratereach that decision themselves. Childrenare carried along by their parents, willynilly, and wives
accompany their husbands though it tears them away from environments they love. There are clearlystages in the life cycle in which the positive elements at origin are overwhelmingly important in limiting migration, andthere are times in which such bonds areslackened with catastrophic suddenness.Children are bound to the familial residence by the need for care and subsistence, but, as one grows older, ages arereached at which it is customary to ceaseone stage of development and begin an-other. Such times are the cessation of education, entrance into the labor force, orretirement from work. Marriage, too, constitutes such a change in the life cycle, asdoes the dissolution of marriage, eitherthrough divorce or the death of a spouse.
6Rupert B. Vance, "Is Theory for Demographers*?" Social Forces, XSXI, (October, 1952),9-13. 7Dorothy Swaine Thomas, Research Memorandum on
MigrationDifferentials (New York:Social Science Research Council, Bulletin 43,1938). 5 In the quotations from Ravenstein, "I" refers to the 1885 paper and "11" to the 1889 paper.
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