Estudo feito por Montgomery publicado em 1992 sobre como a diferença da sua posição na rede o auxilia na procura de emprego.

1. Job Search and Network Composition: Implications of the Strength-Of-Weak-Ties Hypothesis
Author(s): James D. Montgomery
Source: American Sociological Review, Vol. 57, No. 5 (Oct., 1992), pp. 586-596
Published by: American Sociological Association
Stable URL: http://www.jstor.org/stable/2095914
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2. JOB SEARCH AND NETWORK COMPOSITION:
IMPLICATIONSOF THE STRENGTH-OF-WEAK-TIESHYPOTHESIS*
JAMEsD. MONTGOMERY
NorthwesternUniversity
Workersfind jobs through personal contacts (weak and strong ties) and formal sources.
Alternativeformulations of the strength-of-weak-tieshypothesis suggest (1) weak ties relay
job offers more frequently than strong ties, or (2) weak-tie offers are drawnfrom a better
distribution.Aformal model shows that bothformulations imply a correlation between net-
work composition and a job seeker's minimumacceptable wage. However, the use of a weak
tie is never associated with higher expected wages under thefirstformulation, and is only
sometimes associated with higher expected wages under the secondformulation. These re-
sults suggest that researchers shouldfocus on job seekers' networkstructures.
Based on the findingthatworkersfrequently independent for-
variable.Moreover,alternative
locate jobs throughacquaintances ("weak mulationsof the strength-of-weak-ties hypothe-
ties") rather than close friends and relatives sis suggest thatjob seekers benefit from weak
("strong ties"),Granovetter (1973, 1974) argued ties for two distinctreasons.Granovetterempha-
thatweakties play an important in determin-
role sized thatweak ties relay usefuljob information
ing labor-market outcomes.Subsequent theoret- more frequentlythan strongties, whereasLin's
ical workin the socialresourcesliterature further formulationsuggested that weak-tie job offers
emphasized the importanceof weak ties (Lin aredrawnfroma different(oftensuperior) distri-
1982). However, Bridges and Villemez (1986) bution.To examinethe empiricalimplications of
and Marsdenand Hurlbert (1988) found no sig- these two formulations the strength-of-weak-
of
nificant relationshipbetween tie strength and ties hypothesis,I offer a formalmodel in which
wages after controllingfor workercharacteris- workerslocate jobs throughboth personalcon-
tics.Consequently, someresearchers haveargued tacts (weak and strongties) and formal (imper-
against the strength-of-weak-ties hypothesis. sonal)methods,buildingon previousworkin the
Bridgesand Villemez (1986), for example,con- economics job-search literature (Mortensen
cludedthat"thestrong-weak dimensionof ties is 1986).'
nottheonly, oreven themostimportant, attribute
of personalrelationships the labormarket....
in THE MODEL:NETWORKSTRUCTURE
Future researchshouldconcentrate exploring
on AND THE RESERVATIONWAGE
and
otherdimensions socialresources theirrole
of
in thejob findingprocess"(pp. 579-80). Becausejob-seekerslackcompleteknowledgeof
Reflectionsuggeststhatthe BridgesandVille- vacanciesandmustrely on information obtained
mez conclusionmay be premature. Whileempir- throughvarious formal and informalchannels
ical analysesof the strength-of-weak-ties
hypoth- to
(e.g., directapplication employers,newspaper
esis havefocusedon the type of tie actuallyused ads,andpersonal economists
referrals), oftencon-
to locate a job (althoughsee Lai, Leung,andLin ceptualizejob searchas a sequenceof wage of-
1990), the "networksas resources"argument fers drawnrandomlyfrom an offer distribution.
(Campbell,Marsden,and Hurlbert1986) sug- (Whenthe nonpecuniary aspectsof employment
gests that networkstructuremay be the crucial differacrossjobs, the "wage"mightbe interpret-
ed as a broaderindexof job quality.)Ifjob search
* werecostlessforbothunemployed employed
and
Directall correspondence JamesD. Montgom-
to
ery, Departmentof Economics, NorthwesternUni- I Boorman(1975) and Boxman,Flap, and Weesie
versity,Evanston,IL 60208. Helpfulcommentswere (1991) presentrelatedmodels of job searchthrough
receivedfromPeterMarsden.Financialsupport from strong and weak ties. Halaby (1988) used a search-
National Science Foundationgrant SES-9109056 is theoreticmodel to examine individuals'decisions to
gratefullyacknowledged. searchfor new jobs.
586 AmericanSociological Review, 1992, Vol. 57 (October:586-596)

3. JOB SEARCHAND NETWORKCOMPOSITION 587
workers, job-seekerswould acceptany offer ex- Suppose that the workerreceives some (po-
ceeding theircurrent wage (or value of leisureif tentiallystochastic)numberof offers each peri-
unemployed)andcontinuesearchingfor a better od. The distribution the highestoffer received
of
job while employed.But if job searchbecomes each periodis represented H(w), with proba-
by
morecostly once a workeris employed,the opti- bility densityh(w). Further, WR representthe
let
mal search strategyis more complex: The job worker's reservationwage and let V represent
seeker sets a minimumacceptable(or "reserva- the worker's"valueof search,"i.e., the present
tion")wage, rejectinganyoffersbelow thereser- value of expectedfutureearningsgiven thatthe
vationwage andacceptingthe firstoffer exceed- workerremainsunemployedat the end of a peri-
ing this wage (Lippman and McCall 1976; od. Given this notation,consider the worker's
Mortensen1986). expectedfutureearningsviewed fromthe startof
Considerthe simplestcase in whichjob search a period (before any offers are received). Be-
is costless for unemployedworkersbut is pro- cause the worker'sexpectedfutureearningsare
hibitivelyexpensiveforemployedworkers. Even by definitionequal to V if no offer exceeds WR
if an unemployedworkerplaces no value on lei- and are equal to wI(1 - B) if the highest offer
sure(so thatthecurrent "wage" zero),thework-
is exceeds WR, the worker'sexpected futureearn-
er might reject a low-wage offer because em- ings are
ploymentwould precludefurthersearch,which
might lead to a betteroffer and higher lifetime WR
earnings.However,thejob-seekerwould gener- f Vh(w)dw+ | 1-B h(w)dw. (1)
ally not wait to receive the maximumpossible 0 WR
offer becauseearningsforegonefromrejectinga
sufficiently "good"offer might exceed the net Now considertheworker'sexpectedfutureearn-
expectedbenefitfromcontinuedsearch.The fact ings viewed fromtheend of thepreceding period
that the job-seeker rejects relatively low-wage (after all offers were rejected). Given that the
job offersbutacceptsrelativelyhigh-wageoffers workerdiscountsfutureearningsby the factorB,
suggeststhe existenceof a criticalwage, i.e., the is
this "valueof search" definedimplicitlyby
reservation wage, at which the job-seekeris in-
different between accepting employment and WR
continuingthejob search. V= fjVh(w)dw+f |WB h(w) dw. (2)
Now consideran unemployedworkersearch-
ing for a job. Two simplifyingassumptionsare
adoptedin thepresentmodel.First,I assumethat Becausetheworker indifferent
is betweenaccept-
theworker searchesonlywhileunemployed.2 Sec- ing a job at the reservationwage and continuing
ond, I ignore the possibility of job dissolutions the job search,V = wR/(l - B). Substitutioninto
such as quits, layoffs, or retirement.Thus, after equation1 yields
acceptingan offer, the workeris assumedto re-
main forever employed in thatjob.3 Assuming
thatthe workerdiscountsnext period's income (1-B)WR=B j(W-WR) h(w) dw (3)
by a factor B < 1, the present value of future R
earningson a job payingwage w is thusequalto
W + SW + +B...
2W = w/(I -_ ).4 whichimplicitlydefinesthe (unique)reservation
wage.5
2The implicationsof on-the-jobsearcharethusleft Equation indicatesthatthe worker'sreserva-
3
for futurework (Mortensen1986, Sec. 3.1). tion wage dependson the density, h(w), of the
I The model could easily be extended to permit
highest-offerdistribution. Abstractingfrom the
exogenously generatedjob loss so that the worker specific channelsthrough whichjob information
returnsto unemploymentwith positive probability flows, economistscommonlytake this distribu-
each period. tion as given (for one exception,see Mortensen
4The assumption an"infinitehorizon,"
of madefor
the sake of mathematical tractability,
implies thatthe I To derive equation3 from equation2, note that
worker'sreservationwage is constantthroughtime.
Unless the workeris nearretirement, presentval-
the
ue of lifetimeearnings(andconsequentlythe reserva- WR ??
tion wage) will be little influencedby changes in (or J dw= V- JVh(w) dw.
Vh(w)
even the existence of) a retirement date. 0 WR

4. 588 AMERICANSOCIOLOGICAL
REVIEW
and Vishwanath1990). But in orderto explore thatPw > ps because a given weak tie is more
the strength-of-weak-ties hypothesis,I derivethe likely to producenew information thana given
highest-offerdistributionfrom more primitive strongtie.7
assumptionson the sources of job information. While Granovetter's assertionseems to im-
Althoughthe analysis could be generalizedso pose a conditionon the offer probabilities, Lin's
thatthe workerreceives offers from an arbitrary "strength-of-ties proposition"appears empha-
to
numberof sources,I assumethatthe workerre- size differences in the offer distributions. Lin
ceives job informationthroughthree channels: (1982) arguedthat "strongties characterize the
strongties, weak ties, and formal (impersonal) intimatesocial circle of individualswith similar
search. characteristics weak ties characterize in-
and the
I assumethatthe workerpossesses woN weak frequent interactions peripheral
and relationships
ties and (1 - o)N strongties. The worker'snet- among dissimilarindividuals"(p. 134). In the
work is thus describedby two parameters: size presentmodel, this suggests that the strong-tie
(N)andcomposition Ineachperiod, work-
(w). the and weak-tie offer distributions have the same
er receives an offer througheach weak tie with mean but that the weak-tiedistribution more
is
probability and througheach strongtie with
Pw dispersed.8 Given a lower bound on the wage
probabilitypsEachweak-tiewage offeris drawn distribution, also suggeststhatweakties may
Lin
froma distribution Fw(w)withprobability densi- providea better(notmerelymoredispersed) dis-
tyfw(w), while strong-tie offersaredrawnfroma tribution opportunities individuals
of for withlow
distribution Fs(w) withdensityfs(w).The worker initialpositions.9(Initialposition might referto
also receives formaloffers by applyingdirectly the worker'sfather's relative wage or occupa-
to M firmsduringeach period.Eachfirmmakes tional status.) Thus, beyond suggesting differ-
an offer with probability formal offers are
PF; ences in the dispersionof the offer distributions,
drawn from a distributionFF(W) with density Lin's theoryalso implies thatthe offer distribu-
fF(w). Thus, the worker's highest offer is less tions may (sometimes)be ranked.'0
thanw only if each offer receivedis less thanw. Returning the model,considerhow changes
to
Assuming that wage offers are drawnindepen- in the networkstructure and cl) influencethe
(N
of
dently, the distribution the highest offer re- reservationwage (WR). (All results are proven
ceived each periodcan be written in
formally theAppendix.) Holdingnetwork com-
position constant,the reservationwage rises as
H(w)= [1 PF[1 -FF(W)]jM network size increases. Intuitively,the worker
[I _pW [IFW (W)]] (N
expectsmoreoffers (fromboth weak and strong
ties) as N increasesandthusthe workerbecomes
[1 - Ps [1 - Fs (w)]](1-(O)N. (4) more selective. AlthoughWR is unambiguously
While I have so far placed no restrictions on 7To generatethis conditionendogenouslyfromthe
the relationship between the offer probabilities presentmodel, one might assume thatjob offers are
or offer distributions equation4, discussions
in sometimes observedby dyads. Because triadbias is
of the strength-of-weak-ties hypothesis by greateramongstrongties, the workeris morelikely to
receive the same offer from two strong-tiefriends
Granovetter (1973, 1974, 1982) and Lin (1982, thanfromtwo weak-tieacquaintances.
1990) suggest two possibilities. Granovetter 8 In the economics literature,
increaseddispersion
(1982, p. 105) assertedthat "ouracquaintances is typicallyformalizedas a "mean-preserving spread"
('weak ties') are less likely to be socially in- (Rothschild and Stiglitz 1970; see also Mortensen
volvedwithone another thanareourclose friends 1986). Formally,the distribution H(w) is a mean-pre-
('strong ties')."6 Accordingly, since weak ties servingspreadof of(w) if
are"moreproneto move in circlesdifferent from x x
one's own," there is a "structural tendencyfor EHIWI = EH4w1 and dw
IIH(w) > | Hf(w) dw
those to whom one is only weaklytied to have 0 0
better access to job informationone does not for all x.
alreadyhave" (Granovetter 1974, p. 52). In the 9Conversely,an upperboundon the offerdistribu-
presentmodel, Granovetter's argument suggests tion implies thatstrongties are betterfor individuals
with high initialpositions.
6 In the languageof biased networktheory,strong 10 sometimes
I rankdistributions thebasisof "first-
on
ties areassumedto have a greater"triadbias"(Fararo orderstochasticdominance." Formally, H(w) stochas-
and Skvoretz1987). tically dominatesof(w) if H(w) <!4(w)for all w.

5. JOB SEARCHAND NETWORKCOMPOSITION 589
betweenthe res-
increasing N, the relationship
in Thus, both the condition associated with
ervationwage andnetworkcomposition depends Granovetter (equation6) and the conditionsas-
sociatedwith Lin (equation8, sometimesequa-
on the offer probabilities offer distributions.
and
As shown in the Appendix, the reservation tion 7) imply thatthe worker'sreservation wage
wage is increasing the proportion weak ties
in of increasesas networkcompositionshifts toward
(o) if relativelymore weak ties. Because the value of
search,which is equal to expected futureearn-
Ps [1 - Fs (w)] -Pw [I -Fw (w)] <0. (5)
ings, is directlyrelatedto the reservationwage,
Thecondition expressed equation impliesthat each conditionimpliesthatweak ties arebenefi-
in 5
WR is increasing o) if
in cial for the job-seeker.Indeed,if networkcom-
position were chosen to maximize futureearn-
Pw >Ps given Fw (w) = Fs (w) for all w, (6)
ings, the workerwould choose an all-weak-tie
or if networkwheneverthese conditionshold.
Fw (w) < Fs (w) for all w given Pw =Ps. (7)
THE USE OF A WEAKTIE AND
Thatis, the reservationwage is increasingin the EXPECTED WAGES
proportion weak ties if weak ties relayjob of-
of
ferswithhigherprobability strong (equa-
than ties The Granovetterand Lin formulationsof the
tion 6) or the weak-tieoffer distribution supe-
is strength-of-weak-ties hypothesiscould be tested
rior to the strong-tiedistribution(equation7). empiricallyby examiningthe reservationwage
Intuitively, increasein the proportion weak
an of of job-seekers:Holding networksize constant,
ties makesthe worker moreselectivebecausethe does the reservation wage rise as the proportion
workerexpectseithermoreor betteroffers. of weakties increases? Echoingthe"networks as
The reservation wage is also increasingin the resources" argument (Campbellet al. 1986), the
proportion weak ties undera second condi-
of modelthussuggestsa linkbetweenthe worker's
1
tion: network structureand labor-marketoutcome.
00 00
However,insteadof focusing on networkstruc-
ture, empiricalstudies of the strength-of-weak-
Pw = Ps, fwfw (w) dw = f wfs (w) dw, (8)
0 0 ties hypothesishave examinedthe relationship
betweenwages and the type of tie actuallyused
and there exists some fv'such that to find a job (BridgesandVillemez 1986;Mars-
den andHurlbert 1988).The absenceof a signif-
> Fs (w) if W< fw icantrelationship betweenwages andtie strength
Fw(w) = Fs (w) if w .=i aftercontrollingfor humancapitalvariableshas
< Fs (w) if W> fw. led theseresearchers doubtthe relevanceof tie
to
strength labor-market
for outcomes.
Thatis, the reservationwage is increasingin the However, these "tests" of the strength-of-
proportion weak ties when both types of ties
of weak-tieshypothesismay be misguided.To ex-
relayofferswith the sameprobability, bothoffer plorethe implications the preceding
of modelfor
distributionshave the samemean,andthe weak- expectedwages, some additional notationis nec-
tie distribution is "more dispersed" than the essary.First,thehighest-offer distribution(equa-
strong-tiedistribution. economists studying
As tion 4) is re-writtenas
job searchhave long recognized,increaseddis-
persion of the offer distributionmakes search H (w) = L4DF(W)]M [DW(W)] (O [(Ds(W)]fI 'N,
more valuable since job seekers are concerned
i.e., where
only with the uppertail of the distribution,
thoseoffersexceedingthereservation wage.Thus,
if the weak-tiedistribution moredispersed,an
is (Di(wj 1 Pi [ I - F. (w)]
-I
increasein the proportion weak ties improves
of }.
for i E {IF,W,S (9)
the worker'schanceof findinga high-wagejob
andthusraisesthe worker'sreservation wage. The densityfunctioncan thenbe writtenas
" AlthoughthisconditionimpliesthatFwis a mean- h(w) H'(w) = gF (W) + gw(W)+ gS (W),
preserving spread Fs, mean-preserving
of need
spreads
condition.
not satisfy this "single-crossing" where

6. 590 AMERICANSOCIOLOGICAL
REVIEW
characteristics. Becausethe precedingmodelab-
gF (W) MpFfF (w) VPF (W)]M_ [VW (W)] (ON
stracts from human capital differences across
[(DS (W)] ( 01, workers,this assumption equivalentto the be-
is
hypothesisim-
lief thatthe strength-of-weak-ties
plies E{ wlW} > E{ wIS}. But analysis of equation
gw (w) o(Npwfw (w) VFF (W)]M
13 demonstrates none of the conditionsas-
that
ON
[(DW(W)] [(DS (W)] (I-o)N, sociatedwith Granovetter Lin are sufficient
and
and to guarantee relationship.
this Indeed,as shown
in theAppendix, condition
the expressedin equa-
gs (W) (1 - o))Npsfs (w) VFF (W)]M tion6 unambiguously impliesthe opposite:If the
[(DW(W)] ON[(DS (W)] (1-(O)N-1. (10) weak-tieandstrong-tie offerdistributions the
are
same, E{wIW} <E{wIS} if pw > ps. Thus, if
Because the worker searchesuntil receiving Granovetter correctthat weak ties are more
is
wage,thework-
anofferexceedingthereservation likely to providenew information arestrong
than
er becomesemployedin a givenperiodwithprob- ties,then,holdingeverything constant,
else work-
ability ers findingjobs throughweak ties will receive
00 lower averagewages.
| h (w) dw. Although this result holds regardlessof net-
WR worksize (N), networkcomposition(o)),andthe
uponemployment,the worker'sex-
Conditional probability obtaininga formaloffer (PF), it is
of
pectedwage can be writtenas instructive considerthe specialcase in which
to
00 the workerholds one tie of each type, i.e., N = 2
J wh(w)dw and o)= 1/2, and never receives offers through
E{w} = WR (11) formalchannels,i.e., PF = 0. Further assumethat
00
the worker almost always receives an offer
| h (w) dw throughthe weak tie, i.e., Pw is close to 1, but
WR
almostneverreceivesan offerthrough strong the
The workeraccepts a job throughchannel i, tie, i.e., Ps is close to zero.In the periodin which
where i representseither F (formal), W (weak an offer is accepted,an individualacceptinga
tie), or S (strongtie), with probability job througha strong tie is thus likely to have
00 received two offers. An individualacceptinga
Jg, (w) dw. job througha weak tie, on the other hand, is
WR likely to have received only one offer. Because
Conditionalupon employment,the probability the expectedhighestoffer increasesas the num-
thatthe workeraccepts a job throughchanneli berof offersrises,the use of a weak tie impliesa
can be written lower expectedwage.
00 Intuitively,then,E{wIS} exceeds E{ w1W} un-
Jgi (w) dw derthiscondition(equation becausethe use of
6)
Pr(i) = WR for i E {F,S,W}. (12) a weak tie indicatesthatthe workerreceived(on
0o
average)fewer offersduringthe periodin which
Jh (w) dw an offer was accepted.But if periods are very
WR
short (implying that the offer probabilitiesare
Conditional upon accepting an offer through close to zero), the workeris unlikelyto receive
channel i, the worker's expected wage can be several offers simultaneouslyand the use of a
written weak tie reveals almostnothingaboutthe num-
00 ber of offers received.'2In the limiting case in
Jwgi (w) dw
E{wli}= WR foriE {F,S,W}.
'2Althoughsomewhatambiguous,periodlengthin
oo
the precedingmodelprobablybest corresponds the
to
|g, (w)dw (13)
WR
amountof time ajob-seekerhas to respondto a firm's
offer. When periodsare long, the workeris likely to
Researchershave assumedthat the strength- hold severaloffers simultaneously.As periodlength
of-weak-tieshypothesisimpliesthatworkersob- approacheszero (implying that the job-seeker must
tainingjobs throughweak ties should receive immediatelyaccept or reject each offer), the proba-
higherwages aftercontrollingfor humancapital bility of multipleoffers becomes negligible.

7. JOB SEARCHAND NETWORKCOMPOSITION 591
which periodlength is infinitesimal,the worker 5 butrejectanofferof 1. Now considerthe work-
will receive at most one offer (throughall chan- er's expectedwage conditioned thetype of tie
on
nels) in each period.In this case, holdingevery- used. Because strong-tieoffers will only be ac-
thingelse constant,E{wIW}= E{wIS . ceptedif w = 5, E IwISI = 5. But the workerwill
While equation 6 always implies E{ wIS > accepta weak-tieofferof either4 or 5. Assuming
E{wIW, theconditions associated withLin(equa- thatthe worker randomly choosesbetweenoffers
tions 7 and 8) do not permit an unambiguous if boththe strongtie andweaktie offersareequal
ranking the meanwages. Two examplesdem-
of to 5, E{wIW}= 4.7 <5= E(wIS}.
onstrate these conditionsareconsistentwith
that
E{wIS} > E{wIW}.To make these examples as Spread
Example2: Mean-Preserving
transparent possible, I assume that the wage
as
offers are discreterandomvariables.However, To show that the conditionexpressedby equa-
examplesin whichoffersaredrawnfromcontin- tion 8 is also consistent with the relationship
uous distributions could be constructed prove
to E IwIS > E IwIW},I againassumeN= 2, X = 1/2,
the same point. andPF = 0. Further assumethatstrong-tieoffers
aredrawn froma three-pointdistribution which
in
Example1: StochasticDominance
fs (1)= 1/4, fs (3)= 1/2, fs (5)= 1/4, (18)
Assume thatthe workerhas one tie of each type
and never receives offers throughformalchan- andthus,
nels, i.e., N = 2, X = 1/2, andPF = 0. Furtheras-
0 forw< 1
sumethatwage offersfromstrongties areequal-
ly likely to be either 1 or 5: Fs(w)= 1/4 for l< w < 3
3~/4 for3? w<5
1 forw?5. (19)
fs (1)=fs (5)= 1/2. (14)
Assume thatweak-tieoffers aredistributedsuch
Thus, the cumulativedistributionof strong-tie that
offerscan be written
fw(1) =fw(2) =fw(4) =fw(5) = 1/4, (20)
0 forw< 1
Fs(w)= 1/2 for I< w<5
andthus,
1 for w > 5. (15)
0 forw< 1
Assumethatoffersfromweakties aredrawn from
a three-point in
distribution which 1/4 forl<w<2
Fw(w) 1/2 for2< w<4
fw (1) = fw (4) = 1/4., fw (5) = 1/2. (16) 3/4 for4< w<5
I forw?5. (21)
This implies the following cumulativedistribu- Comparingthe distribution functions,Fw(w) >
tion of weak-tieoffers: Fs(w) for w < 3 and Fw(w) < Fs(w) for w ? 3.
BecauseE{w I = 3 forbothdistributions, con-
the
0 forw< 1
ditionexpressedby equation8 holds:Fw(w)is a
F. -) 1/4 forl< w<4 "mean-preserving of
spread" Fs(w).
1/2 for4< w<5 Assuming B=.9 andp= .5,WR= 3.538. In this
1 forw?5. (17)
case, as in example 1, the workeraccepts only
Comparing cumulativedistributions, is ap- offersof 4 or 5. Becauseonly strong-tie
the it offersof
parent that Fw(w) "stochastically dominates" 5 are acceptable,E{ wIS) = 5. Again assuming
Fs(w):Fw(w) < Fs(w) for all w. AssumingPw = thatthe workerchooses randomlywhen receiv-
Ps = p, the conditionexpressedin equation7 is ing offersof 5 through bothweakandstrongties,
thussatisfied. E{wIW)= 4.517 < 5 =E{wIS}.
Given assumptions Bandp, the reservation
on
wage andmeanwages can be calculated. ex-For Although theseexamplesestablish thecon-
that
ample,supposeB= .8 andp = .5. Using Appendix ditions expressedby equations7 and 8 are not
equationAl (or the discreteanalog of equation theoretically with the negativefind-
inconsistent
3), the reservationwage is WR= 3.280. In this ings reportedby Bridges and Villemez (1986),
case, the workerwill acceptanofferof either4 or alternative distributional assumptions imply

8. 592 AMERICANSOCIOLOGICAL
REVIEW
E( wIWI> Ef wIS Inthenextexample,I assume empirical evidence. Although little is known
1.
thatwage offers are distributed lognormally. aboutthe shapeof actualoffer distributions, ex-
amplesusing the lognormal(andother)distribu-
Example3: LognormalOfferDistributions tions suggest that the use of a weak tie should
imply higherexpectedwages when the weak-tie
Assume that the offer distributions lognor- distribution eithermoredispersedor stochasti-
are is
mal with means ,UF .75, gw = Us = 1, and stan- cally dominant.
=
darddeviationsaF = 6W= 1, (s = .75. The weak- Lin's hypothesismightbe reconciledwith the
tie distribution thus stochastically dominatesthe empiricalevidence by assumingthatbothof the
formal distributionand is a mean-preserving conditionsassociatedwith Granovetter Lin and
spreadof the strong-tiedistribution. Assuming hold: Pw > Ps and Fw(w) is superiorto Fs(w).
PF=PW=PS = 1,N=6, 0)=.5,M= 8, andB3=.8, Because I have proventhatthe use of a weak tie
it can be shown thatWR = 1.884 and implies lower wages given Pw > Ps and suggest-
ed that a superiorweak-tie distribution implies
Et wIW = 4.185 > Et wIF I = 3.821 higherwages,thesetwo effectsmightoffseteach
other. However, as the next example suggests,
> E(wIS I = 3.159.
the magnitudeof the negativeeffect is likely to
be quitesmall (andmay be statistically insignifi-
Undereitherequation7 or 8, i.e., Fw stochasti- cant in empiricalwork). Thus, the effect of dif-
cally dominatesor is a mean-preserving spread ferences in the offer distributionsis likely to
of Fs, it seems likely thatE(wIWI> E(wISIfor a swampany effect due to differencesin the offer
large class of distributions.)3 Although I have probabilities.
made little progressdefining this class analyti- Althoughresearchers havebeen unableto find
cally, a rather strongconditionon the offerdistri- a significantrelationship betweenwages andthe
butionsthatguarantees inequality present- use of a weak tie after controllingfor human
this is
ed in the Appendix. capital variables, both Bridges and Villemez
(1986) and Marsdenand Hurlbert (1988) report
EMPIRICAL IMPLICATIONS a positive zero-order correlation.If, as Bridges
and Villemez suggest, humancapital variables
The precedinganalysissuggeststhatthe conclu- areproxiesfor social capitalformation, zero- the
sion reachedby BridgesandVillemez (1986) ordercorrelationmight be explainedby differ-
thattie strength a relativelyunimportant
is factor ences in network structureacross workers.To
in labor marketsuccess - may be premature. see this, considera final example in which the
Supposethatweakties arebeneficial becausethey conditionassociatedwithGranovetter holds,i.e.,
are more likely to relay job information as Pw> Ps , while the conditionassociatedwith Lin
Granovetter suggests. In this case, I have estab- does not, i.e., Fw(w) = Fs(w) for all w. Assume
lished that the worker'sreservationwage (and wage offers are drawnfrom lognormaldistribu-
thus expected futureearnings)rises as the pro- tions with meansR = gw = gS = 1 andvariances
portionof weak ties in the worker'snetworkin- a, = a'w = a's = 1. Furtherassume M = 6, B =.8,
creases.But althoughnetworkcompositionis an andpw = .2 > Ps = .1 > PF = .05. The worker's
important determinant labormarketsuccess, reservation expectedwages given severalal-
of and
the use of a weak tie does not imply higherex- ternativeassumptionson the size and composi-
pectedwages. tion of the worker's network are presentedin
While I have shown thatthe use of a weak tie Table 1.
is consistent with lower expected wages even This example illustratesresultsalreadyestab-
when weak-tieoffers are drawnfrom a superior lished:Individualswith large networksand/ora
distribution, Lin's (1982) "strength-of-ties prop- large proportion weak ties in their networks
of
osition" is more difficult to reconcile with the will set relativelyhigh reservation wages. In this
example,suchindividuals also receiverelatively
13 In
the limitingcase in which the workerreceives highexpectedwages. Thisrelationship consis-
is
at most one offer (throughall channels)in each peri- tent with the findingsof Campbellet al. (1986):
od, it is straightforward proveEs wlW) > Es wiS) if Individuals highsocioeconomic
to of statusarelike-
weak-tieoffersaredistributed uniformly [a,b]while ly to have largerbut less tightly knit networks
in
strong-tieoffers areuniformin [c,d] wherea + b > c + thanindividuals low socioeconomic
of status.But
d and b> d. while Et w I is increasingin N and co,Et wIW}is

9. JOB SEARCHAND NETWORKCOMPOSITION 593
Table 1. ReservationWages, Expected Wages, and Prob- ture,heterogeneity thepopulation
in thusinduces
ability of Using Search Method by Network EtwIW} > EtwIS}. This result is driven by the
Structure
differences in the proportionsPr(W)and Pr(S)
Network Structure across workertypes: Workerswith a large pro-
portion weakties (andthushighexpectedwag-
of
Wagesand N=3 N=3 N=6 N=6
Probabilities cl)= 1/3 clo=2/3 co= 1/3 cl)= 2/3 es) are much more likely to use weak ties (and
less likely to use strongties).
Reservation WR 1.679 1.804 2.125 2.310 In this analysis, I have contrastedalternative
wage informaljob-finding methods - weak versus
Expected E{wI 3.847 4.031 4.513 4.785 strong ties - ratherthan informaland formal
wage methods. However, given the symmetryof the
Expectedwage conditionalupon using a model with respect to each of the job-finding
Formal E{wIFI 3.858 4.046 4.525 4.800 methods,the analysisis easily generalized.Par-
method allelingBridgesandVillemez (1986), Corcoran,
Weak tie E{wIW} 3.830 4.019 4.502 4.779 Datcher,and Duncan (1980) found that the use
Strongtie E{wIS} 3.849 4.037 4.517 4.793 of a personalcontactis not associatedwith high-
Probabilityoffinding job througha er wages and concluded that such contacts are
Formal Pr(F) .425 .371 .271 .229 unimportant labor marketsuccess. But if in-
in
method formalandformaloffersaredrawn fromthe same
Weak tie Pr(W) .290 .505 .367 .618 distribution, differencesshould be expected
no
Strongtie Pr(S) .285 .124 .363 .153 in the averagewage acrossjob-findingmethods
used.Networkstructure, however,shouldbe cor-
relatedwith wages if personalcontactsincrease
the offer arrivalrate.
equalto Et wISI for each network
approximately
structure.14
CONCLUSION
Assume that the labor force comprises two
typesof workers: have small,mostly strong-
half Bridges and Villemez (1986) argued that tie
tie networks(N = 3, co= 1/3) while the otherhalf strengthis not an important dimensionof social
havelarge,mostlyweak-tienetworks(N = 6, co= capitalbecausetheyfailedto find a positiverela-
2/3). The formergroupis represented column
by tionshipbetweenthe use of a weaktie andwages
1 in Table 1 andthe lattergroupis representedby after controllingfor workercharacteristics. My
column 4. The mean wages for the population analysis, based on an economic model of job
can be written search,suggeststhatthis conclusionmay be pre-
mature. Alternative of
formulations the strength-
E (wIW} = SPr(W)EIwIWI of-weak-ties hypothesis suggest that weak ties
X Pr(W) may be beneficial for two distinct reasons.
Granovetter emphasized weakties relayuse-
that
(.290)(3.830) + (.618)(4.779) ful job information more frequentlythan strong
.290 + .618 ties, whereas Lin's formulation suggests that
= 4.476; weak-tiejob offers are drawnfrom a different
(oftensuperior) AlthoughLin's for-
distribution.
mulationseems difficult (althoughnot theoreti-
E IwISI = EPr(S) Et wISI cally impossible)to reconcilewith the empirical
I Pr(S) evidence on wages, Granovetter'sformulation
-(.285)(3.849) + (.153)(4.793) implies that the use of a weak tie will be nega-
.285 + .153 tively (although perhapsweakly)relatedto aver-
= 4.179, age wages.
My analysis suggests that researchers should
where the summationsare taken over worker devotemoreattention therelationship to between
for
types.Intheabsenceof controls network struc- networkstructureand labor-market outcomes.
The relationship betweenwages andthe use of a
14 This resultwould still hold if the common offer particular job-findingmethodmay be counterin-
distribution improvesas N or corises as suggestedby tuitive:The use of a weaktie couldbe associated
Lin's (1982) "strength-of-positions proposition." with lower wages even though weak ties relay

10. 594 REVIEW
AMERICANSOCIOLOGICAL
offersmorefrequently thanstrongties andweak- Appendix
tie offersare(on average)superior offersfrom
to
othersources.However,the presentmodel pre- NetworkStructureand the ReservationWage
dicts an unambiguous relationshipbetween res- Integrating parts,equation3 may be rewrittenas
by
ervation wages and network structure:Both ,00
Granovetter's and Lin's formulations of the (1-B)wRH ={ f l-H(w)dwj ' (Al)
strength-of-weak-ties hypothesisimply that the tWR)
reservation wage rises as the proportion weak
of wherewWH the reservation
is wage corresponding theH(w)
to
ties in a job-seeker'snetworkincreases. distribution.
Consideran alternativeoffer distribution,M(w),where
Economicmodels of job searchseem to offer 00 00
a useful framework examinationof the rela-
for f I - H(w) dw > | I - M(w) dw for all x, (A2)
tionshipbetweensocialnetworksandlabor-mar- x x
ket outcomes.By relaxingseveralof the simpli- or stateddifferently,
fying assumptionsadoptedin the presentanaly- 00
sis, researchers could addressa varietyof other J H(w) - H(w) dw <0 for all x. (A3)
x
issues raisedin the strength-of-weak-ties litera- wage for the M(w)distribu-
Let wHrepresent the reservation
ture. Extendingthe model to permiton-the-job tion so that
searchwould allow examination the relation-
of
ship betweenthe type of tie used, priorwage (or (1-awe=~ fJ1- (w) dwj. (A4)
prestige), thecurrent
and wage (Wegener1991).'5 tR)
Further,by specifying the costs of searching
I establishwiH> wf If
Hby contradiction. wWH WH, inequal-
<
through alternativechannels(as in Holzer 1988),
ity A2 implies that
researchers could examineGranovetter's (1974,
00 00 00
p. 54) claim that unemployedjob-seekers are
morelikely thanemployedjob seekersto turnto f 1 -Hw) dw < f 1 H(w) dw < f I-H(w) dw (AS)
WR WR WR
their strong ties.'6 Alternatively,contact status
could be incorporated the model to evaluate
in Thus, the right-hand side of equationAl exceeds the right-
Lin's (Linet al. 1981;Lai et al. 1990) pathanal- hand side of equationA4. However, underthe assumption
that w H < WH, the left-handside of equationA4 must (at
yses. Finally,following Marsdenand Campbell
least weakly)exceed the left-handside of equationAl. This
(1990), future researchcould incorporateboth contradictionestablishes that w H cannot be less than or
sides of the labormarket employersas well as
-
equal to (i.e., must exceed) wRf.
workers- into the analysis. Once recruitment SupposethatH(w) represents offer distribution
the given
methods and wage determinationare endog- networksize NH and f(w) representsthe distribution given
enized,researchers couldexaminetheinteraction networksize NL whereNH > NL.Fromequation9,
betweensocial networkstructure the income
and H(w) - Hf(w)= H(w) [['14W(W)I)(NH -NL)
distribution (Mortensenand Vishwanath' 1990;
Montgomery1990, 1991a, 1991b). [(T>S(W)](l-())(NHNL) _- I] (A6)
JAMESD. MONTGOMERY AssistantProfessorof Eco-
is Because the bracketedexpression is negative for all w,
nomicsand a FacultyFellow at the Centerfor Urban inequality A3 holds. Holding network composition con-
Affairsand Policy Researchat Northwestern Univer- stant, the reservationwage is thus increasing in network
sity. In his research he explores the relationshipbe- size.
tween social networksand labor-marketoutcomes, Now let M(w) representthe highest-offer distribution
attemptingto integrate economic and sociological when the workerhas 0N weak ties and (1 - o)N strongties;
conceptionsof labor markets.Building upon ethno- H(w) representsthis distributionwhen the workerhas one
graphicaccountsof urbanpoverty,he is also working additionalweak tie (and thus one less strongtie). Equation
9 implies
to develop rational-choice models of "underclass"
behavior. H(w) - M(w) = [(Dw(w) - (Ds(w)] H(w) (A7)
(Ds(w)
15 Note that a job-seeker's currentposition may
Because H(w)/'Ds(w) is always positive, H(w) - M(w)is
also influence networkstructure, offer distributions, negative (and thus WR is increasingin w) if the bracketed
and offer probabilities. expression - which is rewrittenas ps[l - Fs(w)] - Pw[l-
16 The increaseduse of strongties may be relatedto Fw(w)] in equation5 - is negative. Holding networksize
liquidityconstraintsfaced by unemployedjob seek- constant,the conditionexpressedby equation5 implies that
ers, which imply that the reservationwage is falling the reservationwage increases as the proportionof weak
over time (Mortensen1986, pp. 859-61). ties increases.

11. JOB SEARCHAND NETWORKCOMPOSITION 595
Now assumethe conditionexpressedby equation8 holds 00
and let Pw = ps = p. From inequalityA3 and equationA7, fw [x(w) - x(w)] ,(w)dw
WR is increasingin 0) if WR
0o
00
x
J p [Fw (w) - Fs (w)] ['tF (W)]M [I (W)]WN
> w|[x(w) - x(w)] ,(w)dw = O
WR
if dx(w) / dw > O
[(DS(W)](' - co)N-IdW < 0 for all x. (A8) 0o
<w J[x(w) - x(w2)] ,(w)dw = 0 if dx(w) / dw < 0.
Because the last three terms in the integrandare positive WR (A14)
andincreasingin w, andbecause the conditionexpressedin
equation8 implies [Fw (w) - Fs (w)] < 0 if andonly if x > w, Assume thatthe conditionexpressedby equation6 holds
the left-handside of inequalityA8 is less than and let Fw(w) = Fs(w) = F(w) with densityf(w) for all w.
The expected wages are thus given by equationsAlO and
P [DF (0)] [DW (0)]()N [(DS (0)](I - o))N- I
Al l where
J
00
x(w) = (Ds(w)A1Dw
(w)
[Fw (w) - Fs (w)] dw. (A9)
x = [1 - ps[l - F(w)]]/[l - pw[l - F(w)]],
and
Because the conditionexpressedby equation8 implies that
00 t(x) = flw) ['Dr (W)]M [(w (w)]
f [Fw (w) - Fs (w)] dw = 0, [(Ds (w)10 -1))N-I dw. (A15)
0
0o Because dx(w)/dw=f(w)(ps - pw)/Vtw(w)]2 < 0, equation6
J
x
[Fw (w) - Fs (w)] dw <O for all x 2 w, implies E(wISI > E(wIWI.
Now consider the conditions expressed by equations7
and 8 which imply Pw = Ps = p but Fw(w) ? FS(w). The
and
x expected wages are again given by equationsA10 and A 1I
J0
[Fw (W)- Fs (w)] dw >O for all x < w,
where
fw (w) (Ds(w) aln(Dw (w))Iaw
x(w) ==
the integralin expressionA9 is negative for all x. Since all X()-(w (w) fs (w) Dln((Ds
(w)O/w
otherterms in expressionA9 are positive, inequalityA8 is
and
satisfied:the conditionexpressedby equation8 implies that
WR is increasingin (0. t(W) =JS(W) PDF (W)] PDW (W)] [(DS (W)]l @)N-I dw.
(A16)
OfferDistributions, ExpectedWages
OfferProbabilities, and
Suppose thatthe expected wage functionscould be written Thus, dx(w)/dw> 0 is a (sufficient)conditionguaranteeing
as EIwIWI> EI wISI. A relatedcondition- log concavity of
the offer distribution- arises frequentlyin the job-search
Etw1WI = w x(w) ,(w) dw/ 7x(w) t(w) dw, (AIO) literature(Burdett1981; see also the discussion of log con-
WR WR cavity in Heckmanand Honor61990). However,numerical
and examples (not reportedhere) using the normaland lognor-
00 00 mal distributions gw 2 gs andaw 2 as generate Iw1WI
with E
EIw1SI= ,fw ,(w)dw/ Jf(w) dw, (All) > El wISI even thoughx(w) is sometimesnot monotonically
WR WR increasing.This suggests that a weaker (sufficient) condi-
may be found.
tion on the offer distributions
wheret(w) ? 0 for all w andx(w) is continuousand mono-
tonic. Note thatE{wlWI = E{wISI if x(w) is simply a con-
stant.To show thatE IwIWIis greater(less) thanE IwIS if
I
such that
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