WIC, which began as a 2-year pilot program in 1972 and was authorized as a permanent program in 1974, is part of the nutrition safety net available to low-income women and their children. FNS provides annual cash grants for food benefits and nutrition services to fund program operations at 88 state- level WIC agencies (including agencies in all 50 states, the District of Columbia, American Samoa, the Commonwealth of Puerto Rico, Guam, the U.S. Virgin Islands, and 33 Indian Tribal Organizations). Some of these state-level agencies—those that operate the program at both the state and local levels—retain all of their federal WIC grants. Most state-level agencies, however, retain a portion of their grants and pass the remaining funds to over 1,800 local WIC agencies. In fiscal year 2000, about $2.8 billion in federal program funds were used to provide food benefits to participants. Typically food benefits are in the form of vouchers or checks that participants can use to obtain approved foods at authorized retail food stores. An additional $1.1 billion in federal funds were used for nutrition services and program administration. Program administration includes, among other things, activities related to accounting and record keeping, outreach, monitoring and financial audits, and general management. Nutrition services include activities related to determining participants’ eligibility and issuing food benefits, as well as the following: Nutrition education: WIC offers classes, counseling, and other activities to teach participants about proper nutrition, positive food habits, and the prevention of nutrition-related problems. Breastfeeding promotion and support: To promote breastfeeding, WIC offers individual and group counseling sessions at WIC clinics or the hospital. Breastfeeding support can include telephone or in-person consultation with breastfeeding mothers. Referral to health care and social services: WIC agencies provide participants with information on health care and social services and refer them to providers including immunization clinics and the Food Stamp and Medicaid programs. By law, spending for nutrition education and breastfeeding promotion and support activities combined must equal at least one-sixth of a state’s total annual expenditures for nutrition services and administration plus a target amount for breastfeeding promotion and support that is established by FNS at the beginning of each fiscal year. There is no minimum spending requirement for referral activities. Over the past 20 years, government agencies such as USDA, the Centers for Disease Control and Prevention, and GAO, as well as universities and private research organizations, have conducted a substantial body of research on the effects of the entire WIC program. Some of the accumulated body of WIC research and evaluations provides nationwide assessments of WIC’s effects. Most of it has focused on the effect of program participation on birth outcomes and the nutritional status of program participants. USDA has a review under way describing and assessing research on the diet and health outcomes of its nutrition programs, including WIC. The results of this review, set for release later this year, will provide detailed information on over 70 studies, most of which examine WIC’s effects on birth outcomes or on the nutrition status of participants. While the USDA review will not focus on the impacts of specific nutrition services, it will include studies that examined the WIC program’s effects on the initiation and duration of breastfeeding and the immunization status of children. These two health-related outcomes are directly linked to two of the three nutrition services addressed in this report—breastfeeding promotion and support and referral services. However, because the USDA review is generally focused on overall program impacts, its report probably will not include descriptions or assessments of many of the demonstration studies included in this report. The 19 studies we identified included almost twice as many demonstration studies as impact studies. Of the 12 demonstration studies, 3 look at special interventions in nutrition education, 6 look at special interventions in breastfeeding promotion and support, and 3 look at special interventions in referral to health and social services. Of the seven impact studies, one examines nutrition education, four assess breastfeeding promotion and support services, and two evaluate WIC health referrals. Most of the studies have a relatively limited geographic scope. Among the 12 demonstration studies, 11 are at the substate level. They generally study multiple WIC sites and/or multiple counties, but without sufficient sampling rigor to draw valid statewide conclusions. The results of one demonstration study are generalized to an entire state. Among the seven impact studies, three are at the substate level, one is statewide, and three are national in scope. The 19 studies received funding from various sources. Table 1 provides details on project funding for the 12 demonstration studies and 7 impact studies. Appendix II provides detailed information on the funding sources for the 19 studies reviewed for this report. While all 19 studies suffer from methodological limitations, those limitations have varying consequences. Despite their limitations, the results of the 12 demonstration studies suggest that special interventions have some potential to improve nutrition service effectiveness over WIC interventions typically used; though, based on our analysis of these studies, it appears that additional resources may have to be committed to achieve this added effectiveness. However, the methodological limitations of the seven impact studies enable them to provide only very limited information on the effects of any one nutrition service. Appendixes III and IV contain lists of the demonstration and impact studies, respectively, reviewed for this report. The 12 demonstration studies evaluate a range of different special interventions. To varying degrees, all were more effective than usual WIC interventions. Examples of the special interventions include the following: Breastfeeding promotion and support. Gross and others evaluated special interventions designed to encourage breastfeeding among African-American WIC participants. Mothers in the three special intervention groups were provided a motivational video or peer counseling or a combination of the video and counseling. Mothers in the control group received the standard WIC service that incorporated encouragement and support to breastfeed and brochures about breastfeeding during discussions about infant feeding. Mothers in the special intervention groups were twice as likely as mothers receiving the standard WIC infant feeding education to be breastfeeding 8 weeks and 16 weeks after giving birth, even accounting for factors that could increase breastfeeding duration, such as prior breastfeeding experience. Health referrals. Birkhead and others evaluated two special interventions designed to increase the number of WIC-eligible children who receive measles immunizations. The special interventions included having WIC staff escort children to an on-site immunization clinic and a food voucher incentive in which WIC staff provided only a 1-month supply of vouchers to parents, rather than the usual 2-month supply, until the parents provided documentation that their children’s immunizations were up-to-date. The standard WIC immunization referral consisted of notifying parents that immunizations were due, providing information on the benefits of immunizations, and providing the names and telephone numbers of local health facilities that immunize children. Children at escort sites were about five times more likely to be immunized than children at standard referral sites; children at voucher incentive sites were about three times more likely to receive immunizations. Nutrition education. Havas and others evaluated a special intervention designed to increase WIC participants’ consumption of fruits and vegetables. The special intervention—Maryland’s “5-A-Day” program— was a series of three 45-minute group sessions taught by former WIC participants, or “peer educators,” that incorporated special visual materials and included direct mailings to participants. The standard service generally included less than 10 minutes of nutrition education conversation between WIC staff and participants when they picked up their food voucher every other month. Compared to participants receiving the standard WIC nutrition education program, participants exposed to the special intervention displayed a significant increase in nutrition knowledge and in the consumption of fruits and vegetables. Each of the demonstration studies we reviewed suffers from methodological limitations that, while not invalidating the study’s findings, should be taken into account. The limitations we identified are common in studies that attempt to assess the extent to which social or health program interventions—not other factors—are responsible for changes in program participants’ behaviors or health. The major methodological limitations of the demonstration studies we reviewed include the following: Lack of control group. To help isolate the effects of an intervention, an evaluation study must compare people receiving the special intervention to similar people receiving standard WIC services. The difference between these groups can provide insight into whether the special intervention is more effective than standard WIC practice. Not having such a comparison obscures the relationship between the intervention and participant outcomes. Four of the studies we reviewed had a weak research design associated with a lack of control group. For example, Hoekstra and others attempted to evaluate the effectiveness of a new voucher incentive program in increasing WIC children’s rates of immunization. However, the researchers did not compare the group receiving the special intervention to a group receiving standard services. Instead, they compared three special intervention groups to themselves at different points in time over a period of 14 months. Without a control group that does not participate in the voucher intervention, it is difficult to attribute any changes the researchers noticed to the special intervention. Inappropriate data analysis techniques. The analytic techniques used in a study must suit the available data and the research design—in particular, they should be selected for their ability to help isolate the effects of the intervention. Three of the demonstration studies we reviewed used questionable analytic techniques. For example, Havas and others found that a special peer counselor program was effective in increasing nutrition knowledge and the consumption of fruits and vegetables. To reach this finding, Havas and others compared the average fruit and vegetable consumption of the special “5-a-Day” group to the average fruit and vegetable consumption of a group exposed to the standard WIC nutrition education. The comparison, which examined the linkage between demographic characteristics, such as race, and fruit and vegetable consumption, did not take into account the simultaneous influence of other characteristics, such as education level, on consumption. Without an analysis technique, such as multiple regression, that can account for the influence of several factors at once, determining the extent to which the observed differences in fruit and vegetable consumption are the result of the “5-A-Day” program is greatly complicated. Selection bias. Ideally, study participants should be randomly assigned to intervention and control groups to ensure that all participant characteristics will, on average, be the same from one group to another. A selection bias exists if the two groups differ in some systematic way. Selection bias makes it more difficult to attribute an observed difference in outcomes between the two groups to any one factor, such as the intervention. Six of the demonstration studies we reviewed have a possible selection bias. For example, Tuttle and Dewey examined the influence of a new, culturally sensitive breastfeeding education intervention on the initiation and duration of breastfeeding among Hmong WIC participants in Northern California.10, However, the study’s research design depended on women to volunteer to participate in the study—the women self-selected themselves to participate in the special intervention. Thus, those choosing to participate in the special intervention may have shared characteristics (for example, an already existing inclination to breastfeed) that did not exist in those women who chose not to participate. If present, selection bias could lead the researcher to overstate the benefits of the special intervention. Cynthia Reeves Tuttle and Kathryn G. Dewey, “Impact of a Breastfeeding Promotion Program for Hmong Women at Selected WIC Sites in Northern California,” Journal of Nutrition Education, Vol. 27, No. 2 (1995), p. 69. to agree. Excessive missing data, or poor response rates, may skew research findings. Missing data or poor response rate was a limitation in five of the demonstration studies. For example, Ahluwalia and others evaluated five new breastfeeding interventions, and attributed significant improvements in breastfeeding initiation to them. However, the database employed by the study contained breastfeeding initiation data for only 52 percent of the women in the sample. Measurement error. For an analysis to produce reliable results, the measures in the analysis must be accurate. Measurement error is the difference between a measured value and its true value. Five of the studies have potential measurement errors. For example, Shaw and Kaczorowski sought to examine the effectiveness of a peer counseling program on breastfeeding initiation and duration by asking new mothers to recall interactions with breastfeeding peer counselors that took place at the time of birth. Mothers were interviewed 6 weeks to 6 months after giving birth. If memory lapses occurred, new mothers may have incorrectly recalled their dealings with peer counselors, thereby potentially introducing measurement error into the data. Appendix V shows the major findings and methodological limitations of each of the 12 demonstration studies. Our analysis suggests that the effective interventions described in the demonstration studies may cost more than standard WIC approaches. For example, most breastfeeding special interventions were specifically designed to increase the amount of counseling and support provided to prenatal and postpartum women. Although only one of the demonstration studies provided information about the additional costs associated with such interventions, it is reasonable to expect that such one-on-one support will cost more than the standard WIC program. Two of the demonstration studies help to illustrate the linkage between resource commitment and results achieved. The first, Ahluwalia and others, which found that a hospital-based strategy providing bedside support and counseling to women who had just given birth, was the most effective at increasing breastfeeding initiation rates out of five new strategies evaluated. This strategy clearly required more resources than the standard practice of providing counseling and brochures to participants during a visit to the WIC clinic. The second study, Weimer, which was funded by USDA, focused on a special intervention that was similarly resource-intensive. It reported that providing one-on-one support in the hospital after delivery, followed by an in-home visit within 72 hours of birth, increased breastfeeding duration. However, neither study provided any information about the additional costs needed to implement these special interventions. Only one of the 12 demonstration studies we reviewed, Hutchins and others, provided any information about the costs associated with the implementation of the special intervention. This study reported that vaccinations increased at sites providing vaccination screening and voucher incentives (until their children are immunized, a family must visit the clinic monthly—rather than every 3 months—to pick up WIC vouchers). This study uses what its authors term “crude” cost-effectiveness ratios to estimate the average cost for each additional child with up-to-date immunizations. These costs range between $30 and $73, depending on the number of enrolled children and rates of active participation. The seven impact research studies we reviewed provide few conclusive insights into the recent effectiveness of WIC breastfeeding promotion and support, referral services, or nutrition education services. Three of the four impact studies that focused on breastfeeding promotion and support—Schwartz and others, Balcazar and others, and Timbo and others—use old data from the 1988 National Maternal and Infant Health Survey. Although, according to FNS officials, this survey represents the most recent data available, much has changed in the program since 1988, including the characteristics of WIC participants and the emphasis the program places on breastfeeding. As a result, these studies’ findings shed little light on the program’s current effects. Although the fourth study, Wiemann and others, uses data from the mid-1990s, its limited scope, in terms of geography and participants, constrains the applicability of its findings. This study, with data collected from 684 adolescent mothers who gave birth at a hospital in Galveston, Texas, could have some specialized usefulness, but would have to be replicated at many other sites to provide insights into the broader effectiveness of WIC’s breastfeeding promotion and support services. In addition, since adolescent mothers comprise only about 11 percent of all WIC mothers, the study’s focus on them further compromises its more general usefulness. Taken as whole, the inconsistency in the findings of these four studies further limit their usefulness in assessing the effects of WIC’s breastfeeding promotion and support program. For example, Wiemann and others and Balcazar and others find that WIC enrollment is a significant factor in some mothers’ decision to bottle-feed, while Timbo and others, and Schwartz and others, conclude that WIC participation increases breastfeeding. No consistent message emerges from the studies. The two referral service impact studies have methodological constraints that, to varying degrees, limit their usefulness in assessing the effectiveness of WIC referral services. The first study, Suarez and others, using survey data from 30 counties in Texas, found that children who are enrolled in WIC are significantly more likely than children who are not enrolled to be up-to-date on their immunizations, regardless of other intervening factors such as the child’s age, ethnicity, or the family’s income. Although this study likely contains some measurement error, it provides at least limited evidence that WIC referral services are effective in increasing immunization rates. In contrast, due to major methodological problems, the second referral study, McCunniff and others, provides little useful information on the effectiveness of WIC referral services. This study is based on self-administered questionnaire data collected from a sample of mothers at three WIC sites in Kansas City, Missouri. The study found that when taking into account factors such as WIC referral, child’s age, household size, and availability of dental insurance, only the age of the child had a significant, independent effect on the likelihood that children will visit a dentist. There are two principal limitations to this study. First, almost 40 percent of the sampled children were younger than 1 year old. Because many children less than 1 year of age do not yet have teeth, they are much less likely to have made a dental visit, thus reducing the study’s ability to identify factors associated with dental visits other than age. The second major limitation is the measurement error associated with the reliance on self-reported questionnaire data about visits to the dentist. The study did not attempt to verify questionnaire responses through a review of dental records. The authors suggested that such reviews would have increased the accuracy of the self-reported data. As a result of these serious methodological problems, it is likely that McCunniff and others has only limited relevance to understanding the effectiveness of WIC referral services. The one study that primarily focused on the impact of nutrition education, Fox and others, also examined breastfeeding programs and their effectiveness. However, Fox and others was limited geographically, and had other limitations that reduce its usefulness in assessing the effectiveness of WIC’s nutrition education. For example, its scope was limited in that it focused on pregnant and postpartum women at six WIC sites, in three states. Within this limited context, the study describes program and participant characteristics; the nutrition services offered (including breastfeeding promotion and support); participants’ receipt of and satisfaction with these services; and changes in participants’ knowledge and behaviors between the time of prenatal WIC certification and 4 to 6 months postpartum. The study also attempted to assess the impact of WIC nutrition education on participants’ knowledge and behavior. Although the study concluded that participants’ nutrition knowledge and behavior improved significantly over the course of the study, attributing these changes to WIC is problematic because the study did not use a control group. Instead, Fox and others compared intervention groups at different points in time. The study also concluded that (1) WIC participation did not significantly increase breastfeeding initiation or duration; and (2) women’s decisions regarding infant feeding are strongly associated with intentions formed during pregnancy. Demonstration studies, despite some methodological limitations, provide program managers and policymakers with some useful information about the types of WIC nutrition service interventions that can have positive impacts on participants. However, only one recent demonstration study provides any information on the costs associated with implementing various interventions. Given the limited resources available to provide WIC nutrition services, information about the costs to provide effective services could play a critical role in managers’ decisions to implement the intervention and policymakers’ decisions about funding the intervention. In order to maximize the value of nutrition education, breastfeeding promotion and support, and referral service demonstration and evaluation research funded by USDA, we recommend that the Secretary of Agriculture direct officials responsible for implementing such research to require that this research include an assessment of the costs associated with the special intervention being evaluated. We provided a draft of this report to the Department of Agriculture’s Food and Nutrition Service for review and comment. We met with Food and Nutrition Service officials, including the Acting Associate Deputy Administrator for Special Nutrition Programs. The agency officials generally agreed with the report’s findings and recommendation. However, the officials questioned why our recommendation did not address actions that WIC researchers should take to deal with some of the methodological limitations we identified in research evaluating the effectiveness of WIC services. We believe that USDA has a responsibility to ensure that the WIC and other nutrition program research it funds are of high quality. However, our review was not designed to examine USDA’s policies and procedures to ensure the quality of the research it funds or the practices it employs to promote high-quality research in studies it does not fund. As a result, we are not making any specific recommendations concerning how USDA might improve the quality of WIC research at this time. The officials also provided some technical changes and clarifications to the report, which we incorporated as appropriate. We are sending copies of this report to the appropriate congressional committees; interested Members of the Congress; the Honorable Ann M. Veneman, Secretary of Agriculture; the Honorable Mitchell E. Daniels, Jr., Director of the Office of Management and Budget; and other interested parties. We will also make copies available upon request. If you or your staff have any questions about this report, please contact me or Thomas E. Slomba at (202) 512-7215. Key contributors to this report are listed in appendix VI. To identify recent studies that examine the effectiveness of the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) nutrition education, breastfeeding promotion and support, and referral services, we searched relevant databases, such as National Technical Information Service, Sociological Abstracts, and Wilson Social Science Abstracts. We also consulted with the U.S. Department of Agriculture (USDA) WIC program staff and other program stakeholders, including officials from the National Association of WIC Directors. Through this process, we identified 209 items published from 1988 through 2000 dealing with various aspects of the WIC program. To be used in our review, individual items had to meet each of the following criteria: publication in a refereed medium (for example, a journal article, book or book chapter, USDA-issued report); publication date of 1995 or later; examination of one or more of WIC’s nutrition services (breastfeeding promotion and support, nutrition education, or health referrals); and original analysis of a specific nutrition service’s effectiveness. Altogether, only 19 items met all four criteria. Many—86 of the 190 items we rejected—were published prior to 1995, and therefore do not satisfy our definition of recent studies. (We established 1995 as the cutoff to enable us to better examine the program as it currently operates.) We eliminated the remaining 104 items because they did not meet one or more of our criteria. For example, some items appeared in our literature search as professional papers delivered at conferences; thus, they did not undergo any formal referee process. Other items were published as reviews or summaries of original research, but did not include any original research of their own. Some items do not focus on the effectiveness of specific WIC nutrition services. For example, one study examines the general effects of food programs—including WIC and other food assistance programs such as food stamps—on diet, but does not evaluate the effectiveness of specific WIC nutrition service programs. Once we narrowed the scope of our study, we met with staff in the USDA’s Food and Nutrition Service Office of Analysis, Nutrition and Evaluation to ensure that our methodology did not exclude any important studies. According to these officials, our approach successfully identified all of the major recent evaluation studies on WIC nutrition services. We then conducted detailed reviews of the 19 studies. These reviews entailed an evaluation of each study’s research methodology, including its data quality, research design, and analytic techniques, as well as a summary of its major findings and conclusions. We also assessed the extent to which each study’s data and methods support its findings and conclusions. Funding source(s) Ahluwalia, Indu B., Irene Tessaro, Laurence M. Grummer-Strawn, and others. “Georgia’s Breastfeeding Promotion Program for Low-Income Women.” Pediatrics, Vol. 105, No. 6 (2000), pp. 85–91. Shaw, Elizabeth, and Janusz Kaczorowski. “The Effect of a Peer Counseling Program on Breastfeeding Initiation and Longevity in a Low-Income Rural Population.” Journal of Human Lactation, Vol. 15, No. 1 (1999), pp. 19–25. Gross, Susan M., Laura E. Caulfield, Margaret E. Bentley, and others. “Counseling and Motivational Videotapes Increase Duration of Breast- Feeding in African-American WIC Participants Who Initiate Breast- Feeding.” Journal of the American Dietetic Association, Vol. 98, No. 2 (1998), pp. 143–148. Weimer, Jon P. Breastfeeding Promotion Research: The ES/WIC Nutrition Education Initiative and Economic Considerations. Washington, D.C.: U.S. Department of Agriculture, Economic Research Service, 1998. Grummer-Strawn, Laurence M., Susan P. Rice, Kathy Dugas, and others. “An Evaluation of Breastfeeding Promotion Through Peer Counseling in Mississippi WIC Clinics.” Maternal and Child Health Journal, Vol. 1, No. 1 (1997), pp. 35–42. Reifsnider, Elizabeth, and Donna Eckhart. “Prenatal Breastfeeding Education: Its Effect on Breastfeeding Among WIC Participants.” Journal of Human Lactation, Vol. 13, No. 2 (1997), pp. 121–125. Tuttle, Cynthia Reeves, and Kathryn G. Dewey. “Impact of a Breastfeeding Promotion Program for Hmong Women at Selected WIC Sites in Northern California.” Journal of Nutrition Education, Vol. 27, No. 2 (1995), pp. 69–74. Abusabha, Rayane, Cheryl Achterberg, and Jeannie McKenzie. “Evaluation of Nutrition Education in WIC.” Journal of Family and Consumer Sciences, Winter (1998), pp. 98–104. Havas, Stephen, Jean Anliker, Dorothy Damron, and others. “Final Results of the Maryland WIC 5-A-Day Promotion Program.” American Journal of Public Health, Vol. 88, No. 8 (1998), pp. 1161–1167. Hutchins, Sonja S., Jorge Rosenthal, Pamela Eason, and others. “Effectiveness and Cost-Effectiveness of Linking the Special Supplemental Program for Women, Infants, and Children (WIC) and Immunization Activities.” Journal of Public Health Policy, Vol. 20, No. 4 (1999), pp. 408– 426. Hoekstra, Edward J., Charles W. LeBaron, Yannis Megaloeconomou, and others. “Impact of a Large-Scale Immunization Initiative in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).” Journal of the American Medical Association, Vol. 280, No. 13 (1998), pp. 1143–1147. Birkhead, Guthrie S., Charles W. LeBaron, Patricia Parsons, and others. “The Immunization of Children Enrolled in the Special Supplemental Food Program for Women, Infants, and Children (WIC).” Journal of the American Medical Association, Vol. 274, No. 4 (1995), pp. 312–316. Fox, Mary Kay, Nancy Burstein, Jenny Golay, and others. WIC Nutrition Education Assessment Study: Final Report. Alexandria, Va.: U.S. Department of Agriculture, Food and Nutrition Service, 1999. Wiemann, Constance M., Jacqueline C. DuBois, and Abbey B. Berenson. “Racial/Ethnic Differences in the Decision to Breastfeed Among Adolescent Mothers.” Pediatrics, Vol. 101, No. 6 (1998), pp. 11–23. Timbo, Babgaleh, Sean Altekruse, Marcia Headrick, and others. “Breastfeeding Among Black Mothers: Evidence Supporting the Need for Prenatal Intervention.” Journal of the Society of Pediatric Nurses, Vol. 1, No. 1 (1996), pp. 35–46. Balcazar, Hector, Catherine M. Trier, and Jose A. Cobas. “What Predicts Breastfeeding Intention in Mexican-American and Non-Hispanic White Women? Evidence From a National Survey.” Birth, Vol. 22, No. 2 (1995), pp. 74–80. Schwartz, J. Brad, Barry M. Popkin, Janet Tognetti, and others. “Does WIC Participation Improve Breast-Feeding Practices?” American Journal of Public Health, Vol. 85, No. 5 (1995), pp. 729–731. Fox, Mary Kay, Nancy Burstein, Jenny Golay, and others. WIC Nutrition Education Assessment Study: Final Report. Alexandria, Va.: U.S. Department of Agriculture, Food and Nutrition Service, 1999. McCunniff, Michael D., Peter C. Damiano, Michael J. Kanellis, and others. “The Impact of WIC Dental Screenings and Referrals on Utilization of Dental Services Among Low-Income Children.” Pediatric Dentistry, Vol. 20, No. 3 (1998), pp. 181–187. Suarez, Lucina, Diane M. Simpson, and David R. Smith. “The Impact of Public Assistance Factors on the Immunization Levels of Children Younger Than 2 Years.” American Journal of Public Health, Vol. 87, No. 5 (1997), pp. 845–848. Major finding(s) Scope (timeframe) Major limitation(s) Nutrition education lectures and facilitated group discussions were more effective than brochures at increasing participants’ nutrition knowledge. Facilitated group discussion was more effective than brochures at increasing participants’ confidence in performing specific nutrition related behaviors. Seven WIC clinics in New Mexico (not specified) Havas and others, 1998 Consumption of fruits and vegetables increased after an education program consisting of a series of three 45-minute group sessions taught by paid peer educators and incorporating special visual materials and a direct mailing to participants. Sixteen WIC clinics in Maryland (not specified) Gross and others, 1998 The duration of breastfeeding among African- American WIC participants increased with peer counselor support or viewing promotional breastfeeding videos. Four WIC sites in Baltimore, Md. (1992– 1994) WIC participants increased the initiation of breastfeeding when exposed to (1) an enhanced education program with access to a hotline, (2) a free breast-pump loan program, (3) a hospital- based program with bedside support and counseling after delivery, (4) community coalitions, and (5) peer counseling provided by former participants. State of Georgia (1992–1996) 1. Breastfeeding initiation and duration rates increased after volunteer peer counseling. 2. Breastfeeding initiation and duration rates in Iowa (not specified) 1. Missing data; selection bias 2. Lack of control group; increased after paid peer counseling. Michigan (not specified) 3. Lack of control group 4. Selection bias postdelivery contact with mother in hospital was followed up with support (including home visits) by a specially trained paraprofessional. North Carolina (not specified) increased with culturally appropriate breastfeeding education provided in high school or WIC clinics. 4. Local agency in Guam (not specified) Duration of breastfeeding increased after prenatal nutrition education classes focusing on breastfeeding. WIC clinics in three rural Oklahoma counties (1986) Tuttle and Dewey, 1995 Breastfeeding initiation rates increased among Hmong WIC participants after a culturally sensitive prenatal breastfeeding class and prenatal and postpartum counseling. Seven WIC clinics in three California counties (1991–1992) Major finding(s) Scope (timeframe) Major limitation(s) Breastfeeding initiation and duration increased after counseling and support provided by WIC participants, trained and paid as peer counselors. WIC programs in nine West Tennessee health departments (1996–1997) Clinics with paid peer counselors had higher rates of breastfeeding initiation than clinics without peer counselors. Clinics with a lactation specialist or consultant, and peer counselors, had higher rates of breastfeeding initiation than clinics with only peer counselors. However, the benefits of lactation specialists were offset when peer counselors spent at least 45 minutes with individual participants. Fifty-one WIC clinics in Mississippi (1989– 1993) Children were 5.5 times more likely to be immunized, and immunized more rapidly, at WIC sites where staff escorted children to a pediatric clinic in the same facility for immunization. Children were almost 3 times more likely to be immunized, and immunized more rapidly, at sites with a voucher/check incentive. (Until immunization, a family must visit the clinic monthly, rather than every other month, to pick up WIC voucher/checks.) Six WIC sites in New York City (1991) Immunization rates increased at sites with a voucher/check incentive (until children are immunized, a family must visit the clinic monthly, rather than every 3 months, to pick up WIC voucher/checks). Nineteen WIC sites in Chicago (1996–1997) Vaccinations increased at sites with vaccination screening and a voucher/check incentive (until immunization, a family must visit the clinic monthly, rather than every 3 months, to pick up WIC voucher/checks). Seven WIC sites in Chicago (1991–1993) In addition to those named above, Judy Hoovler, Sara Ann Moessbauer, Corrina Nicolaou, Judy Pagano, Debra Roush, and Eugene Wisnoski made key contributions to this report. The first copy of each GAO report is free. 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Summary: Despite methodological limitations, demonstration studies provide program managers and policymakers with some useful information on the types of Special Supplemental Program for Women, Infants and Children (WIC) nutrition service interventions that can have positive results for participants. However, only one recent demonstration study provides any information on the costs associated with implementing various interventions. Given the limited resources available to provide WIC nutrition services, information on the costs to provide effective services could play a critical role in managers' decisions to implement the intervention and policymakers' decisions on funding the intervention.