Rehabilitation professionals use an evidence-based practice approach to treatment.1 An essential element in this approach is to acquire full-text copies of research articles that answer clinical questions. Rehabilitation professionals read the full-text articles to appraise the quality and applicability of the research before applying the results in practice. Therefore, access to full-text articles is crucial for all rehabilitation professionals to take an evidence-based practice approach to patient care.

Cost may be a barrier to acquiring full-text copies of research articles for individuals and for the libraries of many institutions globally. The content of some journals can only be accessed with a subscription or payment per article (‘toll access’). It has been estimated that access to 78% of medical research was restricted to toll access in 2009.2 This restriction is a type of research waste3 because a large amount of clinical research cannot be accessed to inform practice. A survey of surgeons in the United States, Ghana, Peru, and Thailand revealed that access to subscription journals was poorest in Peru (54% lacked access) followed by Ghana (42%) and Thailand (32%).4,5 Even established institutions in high-income economies, like Harvard University,6 are experiencing difficulty.

Journal publishers are now facing a backlash from research institutions in European countries over subscription costs.7 Some research funding agencies are instituting public access policies that require investigators to make the results of their funded research freely available. For example, the National Institutes of Health in the United States,8 the World Health Organization,9 and the European Research Council10 all mandate publication in freely available full-text articles. While it is difficult to make causal inferences about the impact of these policies, research is being increasingly published in open-access journals.8 Other factors that may have contributed to this shift include progressive policies of some journals11-13 and the perceived open-access citation advantage.14,15

Shifting from toll access to open access for full-text articles increases their usage. This is illustrated well by a trial where subscription-only journals published by the American Physiological Society were randomized to either remain toll access or to become open access.16 The articles in journals assigned to open access had 89% more html full-text downloads and 42% more portable document format (PDF) downloads compared to articles in toll access journals.

Open access for the physical therapy profession could be evaluated using the Physiotherapy Evidence Database (PEDro; pedro.org.au) and PubMed (pubmed.ncbi.nlm.nih.gov). PEDro is a free resource that indexes articles reporting the results of randomized trials, systematic reviews, and practice guidelines evaluating the effects of physical therapy interventions.17 It has equal or better coverage of this research than any other database (including PubMed).18,19 PubMed is a free resource that indexes articles relevant to biomedicine and life sciences that use any research method.20 PEDro and PubMed include links to full text, but the percentage of articles with links to free full text is not known.

An analysis of access to full text must recognize where the user is as free access may depend on geographic location. The World Health Organization's Hinari Programme facilitates access to biomedical research (∼16,000 journals) for countries with low- to middle-income economies.21 In contrast, firewalls in countries like China may restrict access.22

The primary objectives of this study were to: (1) estimate the percentage of articles indexed in PEDro that have free full-text access from at least one of the links provided in the PEDro resource; and (2) compare free access between PEDro and PubMed. Secondary objectives were to determine if free full-text access via PEDro: (1) is better for more-recently published articles; (2) is dependent on geographic location (Australia, Brazil, Nepal, or Spain); (3) could be expanded by adding a link to a PDF locator website; and, (4) is associated with article characteristics.

Free full text could be accessed via PEDro for half the sample of 200 articles (51%, 95%CI: 44, 58). PEDro had slightly higher free access than PubMed (4%, 95% CI: 1, 7). Dividing the sample into 5-year subperiods revealed that free full-text access is not higher among more-recently published articles. Access did not vary by geographic location. Eighteen extra articles could be accessed via a PDF locator website. Article characteristics were not related to free full-text access.

An important strength of our study was that it was an adequately powered random sample from the population of trials, reviews, and guidelines for an entire health discipline. Two aspects of data collection reduced the risk of errors. First, the Excel spreadsheet used for data acquisition was rigorously pilot tested. Second, we double checked all data where there was not 100% agreement between all data collectors.

While data regarding full-text access via PEDro were collected on four continents, the countries used may not be representative of global access to free full text and attempts at free full-text access via PubMed and a PDF locator website were from one country only (ie, Spain and Australia, respectively). Two of the countries were classified as high-income economies by the World Bank (Australia, Spain), one as an upper-middle-income (Brazil), and one as a low-income (Nepal) at the time of data collection.29 Evaluation from additional countries would provide a more detailed global perspective.

We were surprised that access to free full text was not better from Nepal because Nepal qualifies for free access to journals under the Hinari Access to Research for Health Programme. We deliberately attempted to access full text using computers that were not connected to the intranet of an institution to simulate PEDro usage by physical therapists and other rehabilitation professionals who do not have institutional access. In contrast, the Hinari Access to Research for Health Programme is implemented at an institutional level, so rehabilitation professionals working in eligible countries need to be part of an institution to access journals via an institutional subscription to Hinari. Repeating this observational study using institutional access could quantify the differences in access to free full text by physical therapists and other rehabilitation professionals who work within an institution compared to those who work in private practice. Hinari providing access at a country level, rather than at an institutional level, would address this disparity. Alternatively, there may be scope for developing a partnership between PEDro and Hinari that allows for free access to articles indexed in PEDro for physical therapists in countries with low- to middle-income economies.

There was no association between article characteristics and free access to full text via PEDro. This is probably explained by full-text access usually being determined at the level of the journal or publisher, rather than at an article level. Perhaps investigating the association between free access to full text and journal characteristics would be worthwhile.

PEDro is a better source of free full-text articles than PubMed for physical therapists and other rehabilitation professionals wanting to use the results of research to inform their practice. From anywhere in the world, physical therapists with no institutional access to a medical library can access free full text for about half the articles indexed in PEDro using the links provided in the PEDro Detailed Search Results page. This access to free full text, combined with features like coding for area of practice, ranking search results by the rigor of the research design and evaluating the methodological quality and completeness of reporting of trials, helps make PEDro an efficient and useful resource to support evidence-based practice. Individual physical therapists need to engage in life-long learning to develop their skills in using resources like PEDro to their fullest extent.30 The developers of PEDro and other resources need to develop and promote the functionality that will support evidence-based practice. While the PEDro Search Help page includes a video on how to access full text,31 the tutorial has one-quarter of the views of other tutorials, so perhaps more promotion is required. A future enhancement for PEDro could be to add a fifth link to full text that searches for the article using a PDF locator website. This strategy could increase the overall percentage of articles on PEDro with links to free access by about 9%, which could be tested by repeating this observational study after the addition has been made. Access to full-text articles is crucial for all rehabilitation professionals to take an evidence-based practice approach to patient care. Professional organisations that represent and businesses that employ rehabilitation professionals, including physical therapists, could facilitate access to high-quality clinical research by offering subscription access to important journals for their members or employees. Researchers could facilitate access to their articles by choosing to publish in open-access journals. Research agencies could mandate that the results of their funded projects be published in open-access journals.

Our estimates of access to free full text for 51% of articles via PEDro and 47% of articles via PubMed are remarkably similar to 47% for articles indexed in Scopus between 1996 and 2013 that could be downloaded for free in 201414 and 47% for users of Unpaywall in 2017.15 In contrast, our data do not exhibit the consistent increase in free access to full text with time that was evident in the Scopus dataset.14 Two reasons for this could be that some journals may have an embargo period for free full-text access and that some journals that have converted to an open-access model in the past decade also made their existing archives open access.11,32 Sampling error may be another reason why our study did not identify better full-text access among more-recent publications. The study of Scopus evaluated access to 1.25 million articles across a large range of academic fields using automated web scraping technology.14 While we could have increased our sample size to the entire population of articles indexed in PEDro if automation was used, we opted instead for using a manual search to simulate the experience of physical therapy clinicians and to avoid errors that may occur in large scale, automated analyses.

PEDro is a good source of free full-text articles for physical therapists and other rehabilitation professionals, with free full-text access being available for 51% of articles, and this access could be increased by 9% by adding a link to the PEDro Detailed Search Results page for a PDF locator website. This access is slightly (4%) higher via PEDro than via PubMed. Free full-text access via PEDro is not higher among more-recently published articles and did not vary based on geographic location. Article characteristics were not related to free full-text access.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.