Mapping the literature of nurse practitioners

Abstract

Objectives: This study was designed to identify core journals for the nurse practitioner specialty and to determine the extent of their indexing in bibliographic databases.

Methods: As part of a larger project for mapping the literature of nursing, this study followed a common methodology based on citation analysis. Four journals designated by nurse practitioners as sources for their practice information were selected. All cited references were analyzed to determine format types and publication years. Bradford's Law of Scattering was applied to identify core journals. Nine bibliographic databases were searched to estimate the index coverage of the core titles.

Results: The findings indicate that nurse practitioners rely primarily on journals (72.0%) followed by books (20.4%) for their professional knowledge. The majority of the identified core journals belong to non-nursing disciplines. This is reflected in the indexing coverage results: PubMed/MEDLINE more comprehensively indexes the core titles than CINAHL does.

Conclusion: Nurse practitioners, as primary care providers, consult medical as well as nursing sources for their information. The implications of the citation analysis findings are significant for collection development librarians and indexing services.

INTRODUCTION

As revealed by the National Sample Survey of Registered Nurses, nurse practitioners constitute the largest group of four advanced practice nursing specialties [1]. Clinical nurse specialists, nurse anesthetists, and nurse midwives are the other three specializations.

The American Academy of Nurse Practitioners' scope of practice describes the professional role of the nurse practitioner as a provider of nursing and medical services to individuals, families, and groups; a manager of acute and chronic illnesses; and a promoter of health and disease prevention in ambulatory, acute, and long-term care settings [2]. As a primary care provider, the nurse practitioner assesses health status, diagnoses, develops and implements treatment plans, and follows up on and evaluates patient status [3].

In 1965, the Federal Nurse Practitioner Program, funded through title VIII of the Public Health Service Act, was established to respond to the “lack of access to adequate primary care for all Americans” due to an acute shortage of primary care physicians [4]. In response to society's demands for health care, especially for underserved populations, nursing programs focused their graduate-level education on clinical specialty areas in addition to traditional functional roles such as teaching and administration. The first graduate program at the University of Colorado, a cooperative effort between nursing and medicine faculty, resulted in the creation of a new nursing role: the pediatric nurse practitioner [4]. Nurse practitioner programs have since expanded to include additional fields: family, adults, psychiatric-mental health, gerontology, midwifery, women's health, and schools [5].

NURSE PRACTITIONERS TODAY

Nurse practitioners are registered nurses who must obtain, through higher education, a certification or master's degree in their area of concentration as determined by their states' licensing requirements [6]. The National Organization of Nurse Practitioner Faculties establishes curriculum guidelines and program standards [7] and criteria for evaluation of nurse practitioner programs [8]. The American Academy of Nurse Practitioners Certification Program administers national certification examinations for adult and family nurse practitioners. Certified nurse practitioners are recognized by the initials NP-C [9].

Although nurse practitioners acquire advanced academic and clinical proficiencies to enable them to practice independently and responsibly, “self-directed continued learning and professional development beyond the formal advanced education is essential to maintain clinical competency” [10]. Continuing education occurs in several ways: through formal studies and direct contact with peers but mostly through publication of research and expert practices.

The present study is one of several focusing on mapping the literature of nursing, a project sponsored by the Nursing and Allied Health Resources Section of the Medical Library Association. The two-faceted purpose, as described in the overview article [11], is to identify the discipline's core journals and to determine the extent of their indexing in the bibliographic databases most likely to be consulted by nurse practitioners. Mapping the literature through citation analysis is a reliable way of determining the type and currency of resources cited by nurse practitioners in their publications. The results of this study can benefit nurse practitioners in showing the core journals of their field, librarians in developing comprehensive collections, and database producers in improving their indexing coverage by including identified core titles.

A review of the literature yielded few studies related to nurse practitioners' use of the literature. O'Neill and Duffey, through citation analysis, reported on the communication between research and practice components of the nursing literature. From a sample of articles published in 1989, their study identified nineteen journals cited ten times or more [12]. Cogdill reported on the frequency of nurse practitioners' use of information resources including print sources as well as peers [13].

METHODOLOGY

The overview article describes in detail the methodology followed by this study [11]. Representative journals of the nurse practitioner discipline were determined by an informal survey of two nurse practitioners' electronic discussion forums: Npinfo and NP-Clinical. Respondents sent lists of sources for their practice information, which included both nursing and medical journals. From these lists, the final selection was made by comparing titles of journals specific to nurse practitioners in the United States to Allen's key nursing journals list [14] and the Brandon/Hill list of printed nursing journals [15].

Four journals were identified. All appeared in key nursing journals. Nurse Practitioner, the only title on the Brandon/Hill list, was suggested for initial purchase.

• Clinical Excellence for Nurse Practitioners: The International Journal of NPACE: bimonthly journal of the Nurse Practitioner Associates for Continuing Education (NPACE), ceased in 2001 and resumed in 2003 as a quarterly publication

• Journal of the American Academy of Nurse Practitioners (JAANP): official monthly journal of the American Academy of Nurse Practitioners

• The Nurse Practitioner: The American Journal of Primary Health Care: monthly journal published by Lippincott Williams & Wilkins

• Nurse Practitioner Forum: quarterly journal published by W. B. Saunders, ceased in December 2001

The selected source journals are peer reviewed and similar in scope: they contain clinical, research, and practical articles in addition to various columns related to professional issues. However, the percentage of research articles varies, as indicated by Allen, between 3% for Nurse Practitioner and 30% for Clinical Excellence for Nurse Practitioners, with 24% for the JAANP and 10% for Nurse Practitioner Forum [14].

RESULTS

The citation analysis of the four journals generated a total of 14,524 total citations referenced in 704 source articles:

• Clinical Excellence for Nurse Practitioners: 176 source articles yielded 3,623 citations, averaging 21 per article

• JAANP: 156 source articles yielded 3,446 citations, averaging 22 per article

• The Nurse Practitioner: 276 source articles yielded 5,456 citations, averaging 20 per article

• Nurse Practitioner Forum: 96 source articles yielded 1,999 citations, averaging 21 per article

Publication type

The format types represented in Table 1 indicated that journal articles constituted the majority of citations (72%). Books came in second place (20.4%). Government documents (2.1%), Internet resources (1.5%), and miscellaneous items (4.0%) formed the rest.

Table 1 Cited format types by source journal and frequency of citations

Publication date

Table 2 indicates the distribution of cited references by year periods. The 9-year period from 1991 to 1999, including in-press material, comprised 10,474 citations or 72.1% of total citations, of which 15.4% were from 1997 to 1999 and 56.7% from 1991 to 1996. The years 1981 to 1990 yielded 3,196 citations or 22.0% of total citations. The previous decade contained a mere 3.8%, and less than 3% of the citations came from earlier years.

Table 2 Cited format types by publication year periods

Core journals

The application of Bradford's Law of Scattering produced 29 cited journals or 1.9% of the total number, with 3,388 citations in Zone 1; 153 cited journals or 10.1% of total, with 3,481 citations in Zone 2; and 1,337 cited journals, with 3,590 citations in Zone 3. Each zone contained an approximately equal amount of the total citations. Zone 1 contained a very small number of highly productive journals. The larger number of titles in Zone 2 indicated lower productivity. The two zones formed a core list of journals in the nurse practitioners' literature. The journals in Zone 3 were the least representative. Table 3 illustrates the distribution by zones of the cited journals. Table 4 provides the titles in Zones 1 and 2 listed under their official PubMed/MEDLINE abbreviations. Zone 3 titles were excluded because of their large number and very low productivity, however the list is available on request.

Table 3 Distribution by zone of cited journals and references

Table 4 Distribution and database coverage of cited journals in Zones 1 and 2

Database coverage

The indexing coverage scores depicted in Table 4 show that the ranking of the databases varies for titles from Zones 1 and 2. For Zone 1, Science Citation Index provided the most extensive coverage, followed by PubMed/MEDLINE, EMBASE, Health Reference Center, Social Sciences Citation Index, EBSCO Nursing & Allied Health Collection Comprehensive Edition, CINAHL, and PsycINFO. For Zone 2, PubMed/MEDLINE had the best coverage, Science Citation Index was next, followed by EMBASE, CINAHL, Social Sciences Citation Index, Health Reference Center, PsycINFO, and EBSCO Nursing & Allied Health Collection Comprehensive Edition. The ranking of the combined average scores for the 2 zones was almost identical to that of Zone 2, with the exception that EBSCO Nursing & Allied Health Collection Comprehensive Edition ranked 7th and PsycINFO 8th. OCLC ArticleFirst covered 93.5% of both zones and included the 29 journals in Zone 1.

DISCUSSION

Publication type

Journal articles constitute 72% of the cited references. Books are the next largest category (20.4%). However, looking at the latest 10 years, the percentage of books consulted takes the lead with 72.7%, versus 71.2% for journals. These findings indicate that, although nurse practitioners rely heavily on journals for their practice information, they also consult the most recently published books and monographs. More than 50% of the total citations to government documents were published between 1991 and 1996, with 11.3% published after 1997. This might indicate a growing interest in issues and policies related to the profession. As anticipated, references to Internet resources started in the mid-1990s, and their number rose sharply during the last 3 years of the study.

Publication date

Results derived from the citation analysis indicate that 72.1% of the total citations belong to the latest 9 years (1991–1999). Less than 25% of these citations are current to the period of the source journals (1997–1999). For previous years, the number of citations for all publication types gradually decreases with the age of the cited resources. The relation between citing and publication date is consistent with the fact that health sciences publications, particularly those relevant to research and clinical practice, are generally considered dated after 5 to 10 years. Librarians might have to reconsider weeding collections after 5 years as the findings demonstrate that nurse practitioners cite resources 4 to 9 years old at a larger rate than those 1 to 3 years old.

Core journals

These journals constitute a core list of productive journals in the nurse practitioners' literature. The majority of the core journals identified in Zones 1 and 2 belong to medical disciplines. Four out of the 29 Zone 1 titles (13.8%) and 39 out of the 153 Zone 2 titles (25.5%) are nursing journals. Two of the 4 source titles, Nurse Practitioner and JAANP, rank number 3 and number 12, respectively, in Zone 1. The remaining 2, Nurse Practitioner Forum and Clinical Excellence for Nurse Practitioners, rank number 52 and number 93, respectively, in Zone 2. This ranking indicates that nurse practitioners either do not cite or have difficulty locating their own profession's publications. The other two nursing titles in Zone 1 are comprehensively related to advanced practice: Nursing Research and Journal of Advanced Nursing. O'Neill and Duffey report that “authors of research articles tend to cite research articles more often than practice articles, and authors of practice articles tend to cite practice articles more often than research articles” [12], which explains the low ranking of research journals. As mentioned earlier in the description of the 4 source journals, their research content is limited. According to Hicks, nurses who conduct research projects are reluctant to publish their findings [16].

The heavy reliance on medical literature is explained by the origins of the profession and its scope of practice. Nurse practitioner programs were established essentially to alleviate a shortage of primary care physicians. As primary care providers, nurse practitioners must acquire knowledge in nursing as well as in various related medical fields. A glance at the journal titles reveals the multidisciplinary nature of the profession: family medicine, internal medicine, gynecology and obstetrics, oncology, surgery, emergency medicine, research, management, and epidemiology, among others. This variety accounts for the high number of journals included in each zone compared to some of the nursing disciplines covered by the other mapping studies.

Database coverage

Although Science Citation Index shows the most comprehensive coverage for Zone 1 titles, only 1 nursing journal, Nursing Research, is indexed. Science Citation Index coverage is equally poor for nursing titles in Zone 2, with only 2 journals, Research in Nursing Health and Cancer Nursing. While PubMed/MEDLINE emphasizes medical rather than nursing literature, all the nursing titles listed in Zones 1 and 2 are indexed in it. Its extent of coverage for these titles is equal to or less than CINAHL. CINAHL's coverage of medical journals is not comprehensive because it focuses on nursing and allied health. Although the advanced nursing practice journals in Zones 1 and 2 have an index score of 5 (95%–100%) in CINAHL, less than 49% of published articles for Journal of Advanced Nursing were indexed in 1998. Advance for Nurse Practitioners, a free publication for nurse practitioners, is not available to institutions and not indexed in any of the databases except PubMed/MEDLINE. Indexing services might have difficulty obtaining copies. Social Sciences Citation Index appears to provide better coverage of nursing titles than Science Citation Index does. However, the high coverage scores for Science Citation Index and Social Sciences Citation Index probably result from the practice of indexing most of the journal contents, including individual meeting abstracts, whereas PubMed/MEDLINE and CINAHL index selectively. PubMed/MEDLINE does not index abstracts of meeting proceedings; CINAHL generates only one record for all meeting abstracts published in a single journal issue, whereas other indexing services provide individual records for each abstract. Like PubMed/MEDLINE, EMBASE is predominately medical. The remaining databases provide mediocre coverage for the majority of the journals. As expected, the databases with medical emphasis rank higher due to the large number of cited medical journals.

The average indexing coverage score for all journals in both zones shows that, for nurse practitioners, PubMed/MEDLINE appears to be the database of choice, followed by EMBASE and CINAHL. The recommendation would be to query either PubMed/ MEDLINE, EMBASE, or both in addition to CINAHL to avoid indexing disparities. All three databases have structured thesauri to facilitate searching for and retrieving relevant citations. Science Citation Index and Social Sciences Citation Index are good sources for abstracts of meeting proceedings.

CONCLUSION

The present study reveals that nurse practitioners gather information primarily from journals, followed by books. As evident from the diversity of the identified core journals, nurse practitioners exhibit a broad base of knowledge covering both the medical and nursing fields. Collection development librarians should not ignore the need for the medical literature and should consider core medical titles for nurse practitioner collections, especially those related to primary care. Bibliographic database producers might also recognize these needs and improve their indexing coverage of the identified core journals.

With the current emphasis on evidence-based practice and the growing demand for electronic publishing, it would be interesting to repeat this study to determine the utilization and impact of these new resources on nurse practitioners' informational practices.