the costing and funding of longitudinal birth cohort studies

The costing and funding of longitudinal birth cohort studiesAlan Doylea and Jean Goldingb

aThe Wellcome Trust, London, and bCentre for Child and Adolescent Health, Department of Community Based Medicine, University of Bristol,

Bristol, UK

Key to the success of any longitudinal birth cohort study is the availability of appropriate and long-term levelsof funding. The ease or difficulty of obtaining necessary funds to carry out data collection, preparation anddocumentation efficiently will determine the quality of data and the ease with which it is made available forcollaborators. Various strategies for acquiring funding are outlined.

Keywords: costing, research funding, birth cohort studies, government support, grants, access fee, study design, seedfunding.

Background

Establishing a major longitudinal cohort study repre-sents a huge investment in time, effort and intellectualinput, as well as money. The last of these may prove tobe the critical stumbling block. The investment to bemade can be on a substantial scale, as in the case of theNational Children’s Study (NCS) in the USA,1 wherethe numbers to be recruited (100 000) and the intensityof measurement over a 21-year follow-up periodrequire significant investment. However, as we haveshown elsewhere, important birth cohort studies canbe undertaken with much smaller numbers.2

Nowadays, national birth cohort studies (UK,3

Norway,4 US,1 Denmark5) are usually seen at the outsetas long-term investments, requiring a suitable infra-structure to support them. This was not always the case– the early national British birth cohort studies of 1946,1958 and 1970 all started as cross-sectional surveys ofbirths and only later was the idea of following up thechildren developed.6–8 Obviously, it is important toplan the study to be followed into the future, butcosting this does have drawbacks – depending on howmany years of follow-up are costed. The NCS1 initiallyestimated the costs of 21 years of follow-up at $2.7billion, but that had the disadvantage of causing shockat the enormity of the undertaking, and initial rejectionby many scientists who assumed that such a commit-ment would reduce substantially the amount that

would be available for other important researchprojects. Funding bodies rarely commit funds over along timescale, and are likely to be very wary of beingtrapped into a long-term commitment. Consequently,it is wise to have a protocol that has a number ofearly milestones with results that can be presentedto funders together with requests for furtherfunding.

As we point out elsewhere,9 a well-designed preg-nancy cohort study needs a considerable amount ofpiloting, validating and strategic planning before goinginto the field. Funders, however, may be reluctant tofinance this important preparatory work, as they wantall of their investment to lead directly to tangibleresults. There are two possible solutions to this: either(i) the preparatory work is packaged as distinctmethodological projects with discrete end points andfunding sought from one or more sources, or (ii) thestudy obtains funding from bodies that are fully awareof the importance of preparatory work. An example ofthe latter is the Generation R study,10 the plans anddevelopment for which were initiated and fundedby the host institution (Erasmus University).

The strategy

The major national longitudinal studies in developedcountries should ideally be the province of govern-ment funding agencies or very large charitable foun-dations, since they require a level of long-termcommitment to proceed. Having said that, the fundinghorizon can be 5, 3, or in exceptional circumstances just1 year depending upon the initial level of commitment

Correspondence:Dr Alan Doyle, The Wellcome Trust, 183 Euston Road,London NW1 2BE, UK.E-mail: [email protected]

86 doi: 10.1111/j.1365-3016.2008.01011.x

Paediatric and Perinatal Epidemiology, 23 (Suppl. 1), 86–92. © The Wellcome Trust

mailto:[email protected]

to the concept (1 year may be for certain pilot studies/feasibility/validation only). However, once a studyhas started the overall intent should be to continue tosupport it in perpetuity or at least to the conclusion ofsignificant outcomes/end points (5 years minimum).The major caveat to this is the perceived and real levelof outputs to be gained and the productivity of theusers of the resource that is created. A sense of balanceis required on this point as studies need to ‘mature’ togather significant end points over time before theirfull potential can start to be achieved. For example,even with up-to-date computer and data processingfacilities, the gap between completion of initial enrol-ment and peer-reviewed publication of data from thecohort (excluding publication of pilot and validationstudies) is likely to be at least 3 years.

Fortunately, national strategic funding can and doeshappen; however, it can make studies vulnerable tochange in regard to government and scientific policyand priorities. The funders also need to be responsiveto technical changes. For example, the protocol agreedand finalised up to 5 years before a study commenceswill utilise biomarkers and other end points current atthat time. In a fast-moving field this can put a studyat risk of seeming obsolete even at the beginning ofthe study. In the field of genetic epidemiology, socialfactors (e.g. scandal in the case of the historical storageof tissues without consent) can influence public accep-tance of a study.11

Although not a birth cohort, UKBiobank12 (a longi-tudinal study of adults aged 40–69) had an interestingbackground. A partnership funding approach betweengovernment agencies (the Department of Health andthe Medical Research Council) and a major charity (theWellcome Trust) became the driver to take the initiativeforward. It is interesting to note that, in some ways, alarger base of funders can offer a more financiallysecure framework in which to operate, although it maybe necessary to create a suitable organisational struc-ture to carry the project forward. In this case a not-for-profit charitable company was created to provide anarm’s length approach and greater freedom for thedirector to run the study.

Many of the major European national longitudinalbirth cohort studies are created on the basis of soundinitial funding and the expectation of continuinginvestment. Once the study is established, long-termsupport can vary from a simple ‘maintenance’ mode,ensuring only that stored data are available for use bythe scientific community, to further contacts of the

study cohort on a periodic basis with particular endpoints in mind.

An alternative funding model comprises the devel-opment of a range of individual hypothesis-drivenprojects that each contributes, via project grants, tosupport the ‘core’ of activity. As suggested elsewherethis allows for a large project to be launched withoutfully guaranteed long-term support. It represents amuch more complex and managerially difficult path tofollow but it may be the only course available in someinstances, and was the way that the ALSPAC study, forexample, was funded for the first 10 years.13 In suchcircumstances there needs to be recognition, at least bythe institutional host organisation, that the study is partof the overall strategic portfolio of activities of the insti-tute and that there may be a need for occasional top-upfinancial support to ensure that the resource is not putat risk because of short-term financial difficulties.

For scientists based in developing countries thereare additional barriers to funding that need to beaddressed at both the national and the internationallevel. It may be possible to build in the cost of thesestudies in the context of major developmental andenvironmental projects (usually funded by regionalbanks and large donors). The role of internationalorganisations is important in assisting developingcountries to identify sustainable sources of fundingand helps ensure the continuity of the effort. Thecreation of regional and global partnerships can help toraise the profile of the opportunities for collaborationand capacity building. The Gates Foundation (USA),14

the Rockefeller Foundation (USA),15 the InternationalDevelopment Research Centre (Canada)16 and theWellcome Trust (UK),17 for example, have schemes thatcould be appropriate for funding such studies.

Fees for access and income generation

Access by scientific collaborators

An issue that is often raised in the context of biologicaland other data resources is that of income generationand fees for access. In some instances this can be seenas a distraction from the main purpose of the study butfor others it may provide a lifeline to sustainability inthe long term. The reality is that, in most cases, depen-dency upon fees for access is complex and, by its verynature, unreliable. Although it should not be designedas the sole source of funding, any additional income isa boost to the core funding that all studies require.

Costing and funding a longitudinal study 87


There is the expectation that in return for governmentfunding there should be free access to the data, but thisshould be clarified. The points to be considered include:(a) what promises have been made to the participants inregard to who should be allowed access; (b) how reveal-ing of confidential information might the data be; (c)caution concerning the frivolous use of information ifmaterials are available free of charge (especially deple-table biological samples); and (d) avoidance of creatingbarriers to legitimate access. These issues are discussedfurther elsewhere.18 However, it should be borne inmind that even if the study is not charging a fee foraccess, preparing data or biological samples for use by acollaborator has genuine costs that need to be coveredby the collaborator unless this is provided for in theoverall funding of the study.

Access by commercial companies

Access by commercial users should be consideredseparately. The original consent given at the time ofcohort recruitment has to be clearly explicit on thispoint. However, before a decision is made at the plan-ning stage that there should be no commercial access, itis prudent to investigate the full implications of such adecision. There are circumstances that could be envis-aged whereby a commercial company could offer toundertake a major and expensive genotyping or bio-marker study, the results of which would be put intothe public domain and hence be of benefit to the worldat large. A contribution such as this would be pre-vented if the original consent excluded any commer-cial involvement in the study. It is true that someparticipants will not like the idea of a commercialcompany making money from their own goodwill. Thestudy could allow such individuals to make theirconsent conditional on there being no commercialaccess to data arising from their participation. For itspart, the study can make it clear that it would onlyallow commercial access for studies that are likely tocontribute to the common good.

Costing the preliminary components

Phase 1: Planning and strategy

The initial phase of the study is likely to involve anumber of different meetings and discussions (Box 1).This will ideally involve visiting other ongoing studiesin different parts of the world, or inviting representa-

tives of those studies to come and describe how theirstudy was devised and, importantly, what the difficul-ties were. It is useful to discuss the aims of the studywith experts in various fields and what they see asimportant issues (whether this is in a developed ordeveloping economy).

Engagement with politicians is of great importance,but difficult. It should probably only be tried once theimportant health and social issues have been identified,and a rough estimate of costing made. Politicians areusually focussed on short-term results rather than astudy which will only produce valuable information inthe long term. Nevertheless, it is worth trying to firethem with enthusiasm, and to encompass all politicalparties.

Even at this early stage it is important to identifywho the director will be, and where the team will bebased.19 Ideally, this individual should be involved inall the subsequent discussions and decisions.

Phase 1 will cost relatively little, but should includethe funding to visit other studies, as well as key poli-ticians and scientists, and the finances for invitedexperts to meet and advise.

Phase 2: Development of design and instruments

The tasks in phase 2 are outlined in Box 2, anddescribed in detail elsewhere.18,20–25 In decidingwhether data from participants should be obtained by

Box 1. Phase 1: The initial preparations

• Identify the important health, environmentaland social issues

• Identify an appropriate Director who wouldbe enthusiastic and competent in regard tosuch a role19

• Obtain the support of key scientists withinand outside the country for such a study

• Seek the interest of politicians and relevantcivil servants

• Arrange an appropriate institution to whichthe study may be attached19

• Ascertain whether there is a consortium ofcohorts which you could join20

• Invite key people to form an advisory orsteering panel

88 A. Doyle and J. Golding


self-completion postal questionnaire, by interview athome or by telephone22, it is worth looking at the costcomparisons. In general, cost comparisons of the threetypes of data collection have shown that questionnairesdelivered to the home are substantially cheaper thaneither of the other two formats.26 If postal question-naires are contemplated, it is also worth assessing waysof increasing the response rate – for example, it is clearthat in many countries enclosure of a token amount ofmoney with the questionnaire increases the response,27

as does the promise of having the names put into aprize draw if they respond.28 Other types of datacollection may appear to be cheaper (e.g. Internet ormobile phone based questionnaires), but would needto be fully tested and compared.

The costs of phase 2 of the study are still relativelycheap, but staff will need to be taken on. A studysecretary/clerical assistant/personal assistant to thedirector will be important, together with at least threeresearch assistants, one of whom should be versed incomputer technology, one in laboratory skills and one

to review and summarise the relevant literature. Theyshould work with the director and develop instru-ments and techniques as required. The costs other thanstaff salaries will involve those incurred in holdingmeetings and travel where relevant.

Phase 3: Piloting and validation studies

It must be borne in mind that if a pregnancy cohortstudy is designed to obtain all the data required,22 onceenrolment starts the pace becomes very labour-intensive as the data are collected at various timepoints during pregnancy and infancy, and biologicalsamples are collected and stored. Consequently, allthe various measures and processes for the whole ofpregnancy and at least the first 2 years after deliveryneed to be carefully planned, tried and tested,9 thestaff appointed and trained and laboratories set upbefore going into the field (Box 3). The costs of thispart of the study are considerable, but extremelyimportant. This phase will provide the informationneeded to fund the study proper.

Planning for the provision of a long-termsustainable resource

A key point in ensuring the long-term sustainabilityand availability of a resource is that the access andgovernance arrangements are clear and transparentand provide a workable basis for building a soundconstituency of collaborators and users.18 The ultimatestrength of a resource lies in the long-term utility itprovides. The stronger the user base the more impactit has, the greater the number of relevant publicationsand, over time, the greater the wealth of data that accu-mulates. These are all indices of the value added by thestudy to the original financial investment. Thus, whenthe time comes for the funders to review the success ofthe study in these areas, such information will make iteasier to put the case for maintaining and furtherdeveloping the resource.

It must be recognised that there will be a ‘lag’period before scientific gains are made following theinitial financial investment in a study but, at the sametime, studies cannot be seen to roll on without sig-nificant outputs (and appear to be a ‘black hole’ anda financial drain). One way around this is to meetfunder expectations of early returns from the studyby treating it as a series of cross-sectional data collec-

Box 2. Phase 2: Development of design andinstruments

• Review the literature in regard to who isdoing/has done similar studies

• Start formulating the research questions andhypotheses for the study20

• Identify an independent group to act as anethics committee18

• Identify the way in which the study samplewill be chosen21

• Develop the questions to be asked, whetherin an interview, self-completion or electronicformat22

• Identify other sources of information that canbe used by the study22

• Investigate the optimum ways of collectingand storing biological samples23,24

• Start discussing and costing the up-to-dateuses of information technology (IT) in regardto such a study25

• Meet with the ethics committee to discussstructure of consent agreements18

• Estimate the costs of phases 3 and 4 of thestudy, and seek funding for these phases



tions each of which may give value (and publications)before the longitudinal aspect of the study has time tomature.

Data management, curatorship, mentoring andtraining

The continuing maintenance of data and samples canappear to be an open-ended commitment. The directorand key research scientists of the study may decidethat at some stage the long-term nature of resourcemanagement is a distraction from the research aimsand something best performed by others, but it isusually these very people who know the resource bestand whose involvement is essential to maximise its fullpotential. Whatever mechanism is used for long-term

curatorship of the resource, this latter aspect shouldnot be overlooked when estimating the overall costs.

Support by the study organisation for externalusers of the resource requires a range of expertise andscientific knowledge to be effective, and cannot exist inan intellectual vacuum. The value of mentoring andtraining in the use of data derived from cohort studiesshould be a fundamental part of the project plan andfunders should recognise that this is an essential partof data management and a legitimate call uponfunding. Strategically, this needs to be part of the ethosof the institution housing the study; otherwise, theinfrastructure and long-term organisational supportrequired for mentoring and training will not be avail-able. Another consideration is the need for trained per-sonnel who can fulfil these functions and who alsowould need to see this type of activity as a legitimatecareer option; they need to be supported institutionallyin this choice.

It may well be the case that smaller studies wouldfind it impractical to develop user services and in thisinstance could link to a centre capable of doing so.This could provide a better solution for both studyorganisations and users. The result could be a dis-seminated network model with the main ‘centre’ alsoproviding valuable support for study researchers withrelevant strengths in statistics, bioinformatics andinformation technology. The added benefit would bea focus for long-term maintenance of the resourceshould individual or institutional priorities change.Also, last but not least, such a centre may be moreable to develop generic technology and achieveeconomies of scale in material storage and data han-dling. This is discussed further elsewhere in thissupplement.

Conclusion

In conclusion, the financial aspects of creating a longi-tudinal birth cohort study should not be under-estimated. A business planning approach with thenecessary management skills to make the venture suc-cessful can take research scientists into new unchartedareas. This requires hiring the necessary expertiseand providing adequate training – both essential tocombine effective resource management (includingquality assurance) with research skills in order to makefor a successful project that will have longevity, and amajor scientific and public health impact both nation-ally and internationally.

Box 3. Phase 3: Piloting and validation

• Once questions to be asked have been formu-lated, test their reliability and validity using avariety of sources9

• Test the reliability and linkability of data to becollected from sources other than question-naires or interviews (e.g. health records)

• Assess and test ways of tracing peoplewho have moved home frequently and/orchanged their name29

• Carry out pilot studies to assess the feasibil-ity of collection and storage of different typesof biological sample, paying particular atten-tion to labelling24

• Discuss the strategies needed with appropri-ate groups of health care workers – these mayinclude health visitors, primary care physi-cians (general practitioners), obstetricians,midwives and paediatricians

• Engage the local community, including rel-evant cultural, religious and ethnic groups18

• On the basis of the piloting, calculate thecosts of the study itself

• Engage with collaborators

• Seek appropriate funding

• Appoint and train staff

• Initiate and maintain frequent positive mediacoverage29



Acknowledgements

We have greatly benefited from the comments of allwho reviewed the early drafts of this paper: ProfessorThea de Wet, South Africa; Dr Chittaranjan Yajnik,India; Dr Alicia Matijasevich Manitto and ProfessorCesar Victora, Pelotas, Brazil; Drs Jenny Pronczuk andMarie-Noël Bruné, WHO Geneva; Dr Martha Linet,National Cancer Institute, USA; Dr Matthew Long-necker, National Institute of Environmental Health

Sciences, USA; Dr Danuta Krotoski, National Instituteof Child Health and Development, USA.

Funding for the editors to meet and work togetherwas provided by the NIH and the WHO. Costs ofpublication of this supplement were provided byWHO.

Conflict of interest

The authors declare no conflict of interest in this work.

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Summary

• The costs involved in organising a longitudinal birth cohort study are large and should be maintained fora long period, enabling the investigators to encompass a variety of tasks including piloting and validationstudies, organising a depository for biological samples, collecting data from a variety of sources andproviding data to collaborators

• Ideally government funding (from several agencies) should be involved, especially if one can combinethese funds with those provided by charitable or other organisations

• Where long-term funding is difficult to obtain, a variety of short-term project grants can be used, thoughthis is far from ideal

• The fact that long-term studies address environment and development issues calls for the involvementof major donors (e.g. international banks in developing regions)

• Funding of long-term support for curatorship of data and biobanks should be part of the overallstrategy



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the costing and funding of longitudinal birth cohort studies

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