- Systematic review
- Open Access
The use of the PARIHS framework in implementation research and practice—a citation analysis of the literature
Implementation Science volume 15, Article number: 68 (2020)
The Promoting Action on Research Implementation in Health Services (PARIHS) framework was developed two decades ago and conceptualizes successful implementation (SI) as a function (f) of the evidence (E) nature and type, context (C) quality, and the facilitation (F), [SI = f (E,C,F)]. Despite a growing number of citations of theoretical frameworks including PARIHS, details of how theoretical frameworks are used remains largely unknown. This review aimed to enhance the understanding of the breadth and depth of the use of the PARIHS framework.
This citation analysis commenced from four core articles representing the key stages of the framework’s development. The citation search was performed in Web of Science and Scopus. After exclusion, we undertook an initial assessment aimed to identify articles using PARIHS and not only referencing any of the core articles. To assess this, all articles were read in full. Further data extraction included capturing information about where (country/countries and setting/s) PARIHS had been used, as well as categorizing how the framework was applied. Also, strengths and weaknesses, as well as efforts to validate the framework, were explored in detail.
The citation search yielded 1613 articles. After applying exclusion criteria, 1475 articles were read in full, and the initial assessment yielded a total of 367 articles reported to have used the PARIHS framework. These articles were included for data extraction. The framework had been used in a variety of settings and in both high-, middle-, and low-income countries. With regard to types of use, 32% used PARIHS in planning and delivering an intervention, 50% in data analysis, 55% in the evaluation of study findings, and/or 37% in any other way. Further analysis showed that its actual application was frequently partial and generally not well elaborated.
In line with previous citation analysis of the use of theoretical frameworks in implementation science, we also found a rather superficial description of the use of PARIHS. Thus, we propose the development and adoption of reporting guidelines on how framework(s) are used in implementation studies, with the expectation that this will enhance the maturity of implementation science.
There has been an increased use of theoretical frameworks in the field of implementation science in the last decade, with most developed in the last two decades [1, 2]. Tabak et al. identified 61 theoretical models used in dissemination and implementation science . However, while theoretical frameworks are increasingly being cited, more research is needed to understand how they are chosen and applied, and how their use relates to improved implementation outcomes [1, 4]. Variously described in the form of theories, frameworks, or models, all strive to provide conceptual clarity on different aspects of implementation practice and research. For consistency, we will refer to these as theoretical frameworks, or simply “frameworks.”
The Promoting Action on Research Implementation in Health Services (PARIHS) framework is a multi-dimensional framework which was developed to explicitly challenge the pipeline conceptualization of implementation . The PARIHS framework is a commonly used conceptual framework [1, 4] that posits successful implementation (SI) as a function (f) of the nature and type of evidence (E) (including research, clinical experience, patient experience, and local information), the qualities of the context (C) of implementation (including culture, leadership, and evaluation), and the way the implementation process is facilitated (F) (internal and/or external person acting as a facilitator to enable the process of implementation); SI = f(E,C,F). The framework was informed by Rogers’ Diffusion of Innovations  and various organizational theories and theories from social science  and generated inductively by working with clinical staff to help them understand the practical nature of getting evidence into practice. The PARIHS framework was initially published in 1998  and updated based on a conceptual analysis in 2002  and further primary research . A further refinement was undertaken in 2015 , resulting in the integrated or i-PARIHS. Articles using the revised version are not included in the citation analysis reported here. The PARIHS framework has been described as a determinant framework in that it specifies determinants that act as barriers and enablers influencing implementation outcomes . Skolarus et al.  identified Kitson et al.  as one of the two primary originating sources of influence in their citation analysis of dissemination and implementation frameworks.
Despite the growing number of citations of theoretical frameworks in scientific articles, the detail of how frameworks are used remains largely unknown. Systematic reviews of the application of two other commonly used frameworks , the Knowledge to Action framework  and the Consolidated Framework for Implementation Research , both reported that use of these frameworks, beyond simply citation, was uncommon. While PARIHS has been widely cited, it has also been scrutinized; in 2010, Helfrich et al. published a qualitative critical synthesis of studies that had used the PARIHS framework , finding six core concept articles and 18 empirical articles. One of the reported findings was that PARIHS was generally used as an organizing framework for analysis. At the time, no studies used PARIHS prospectively to design implementation strategies . A systematic review applying citation analysis to map the use of PARIHS (similar to those undertaken for the Knowledge to Action framework (KTA)  and the Consolidated Framework for Implementation Research (CFIR) ) has not yet been performed.
Systematic reviews can contribute to the development of existing theoretical frameworks by critically reviewing what authors state as their weaknesses and strengths; they can also direct future and current users of frameworks to examples of using the frameworks in different ways. To contribute to this development from the perspective of the PARIHS framework, we undertook a citation analysis of the published peer-reviewed literature that focused on the reported use of PARIHS (and its main elements), in what contexts the framework has been applied, and what scholars who have used the PARIHS framework (and its main elements) report as its strengths, limitations, and validity.
The method used for this study is citation analysis, i.e., the examination of the frequency and patterns of citations in scientific articles, in this case articles citing the core PARIHS framework publications. A team of researchers with engagement in the development and/or use of the PARIHS framework was constituted. Initially, the group decided on the core publications for the citation analysis. Four articles were selected as they represented the key stages of the framework’s development, namely the original paper that described PARIHS, plus three subsequent papers that informed and outlined revisions to the framework:
Kitson A, Harvey G, McCormack B. Enabling the implementation of evidence-based practice: a conceptual framework. Qual Health Care. 1998;7(3):149-58.
Rycroft-Malone J, Kitson A, Harvey G, McCormack B, Seers K, Titchen A, et al. Ingredients for change: revisiting a conceptual framework. BMJ Quality Saf. 2002;11(2):174-80.
Rycroft-Malone J, Harvey G, Seers K, Kitson A, McCormack B, Titchen A. An exploration of the factors that influence the implementation of evidence into practice. J Clin Nurs. 2004;13(8):913-24.
Kitson AL, Rycroft-Malone J, Harvey G, McCormack B, Seers K, Titchen A. Evaluating the successful implementation of evidence into practice using the PARiHS framework: theoretical and practical challenges. Implement Sci. 2008;3:1.
Citation searches were performed by an information specialist (KG) to retrieve published articles citing any of the four core articles. The searches were performed in two citation databases: Web of Science and Scopus. The first searches were performed between 31 March 2016 and 1 April 2016. Later, 6 September 2019, additional searches were performed in respective databases. These searches were limited to citations that were published 1 April 2016–31 August 2019 to update the result from the first searches. All citations that were published September 1998 (i.e., when Kitson et al 1998 was published)–31 August 2019 (i.e., prior to the search date) in respective databases were collected in EndNote Library. Endnote was used for checking duplicates and retrieving full texts. To manage the scope of the citation analysis, we opted to only include articles in English published in peer-reviewed scientific journals. The searches in Web of Science were, because of the subscription, limited to Web of Science Core Collection without Book Citation Index.
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram  for the data extraction is provided in Fig. 1. Initially, an assessment to identify the articles that used the PARIHS framework in any other way than merely referencing one or more of the core articles was performed (Additional file 1). For this initial assessment, all articles were read in full. After identifying articles where the PARIHS framework was used, data extraction was undertaken using a tailor-made data capture form (Additional file 1). The data capture form was developed and piloted in iterative cycles by the research team. Apart from capturing information about where (country/countries and setting/s) and with whom (professional groups and roles) PARIHS had been applied, the form included questions on whether PARIHS was used in one or more of the following ways:
In planning and delivering an intervention,
In data analysis,
In the evaluation of study findings, and/or
In any other way.
Each of these questions was followed by an open-ended item for extracting information on how this was reported . To enhance reliability and data richness, each reviewer copy-pasted sections of the article corresponding to the open-ended reply into the data extraction form when appropriate and indicated page, column, and row. Two additional items captured whether the PARIHS framework had been tested or validated, as well as any reported strengths and weaknesses of the framework. Thus, we report on what the authors of the included articles claim to have done, rather than a judgment as to how and to what extent they actually used the PARIHS framework.
For data extraction and validation, the research team was divided into four pairs, ensuring that each article was assessed separately by at least two research team members. The pairs received batches of 20 articles at a time. Variations in the assessments were discussed until consensus was reached within the pair(s). Further, queries detected within the pairs were raised and discussed with the whole research team, until consensus was achieved. Regular whole-team online meetings were held to consolidate findings between every new batch of articles and throughout the development and analysis process. In total, the group had > 20 online meetings and four face-to-face meetings from the initial establishment of the group in January 2015.
Categorical data were analyzed using descriptive statistics, whereas the open-ended items were analyzed qualitatively , including the collated extractions of data to illustrate each of the four types of use (i.e., how the PARIHS framework was depicted in terms of (1) planning and delivering an intervention, (2) analysis, (3) evaluation of study findings, and/or (4) in any other way).
Applying a content analysis approach , members of the research team worked separately with the texts extracted from the reviewed articles. The extracts for each open-ended item were read and reread, to get a sense of the whole. Next, variations were identified and formed as categories. Findings for each question were summarized in short textual descriptions, which were shared with the whole team. In a face-to-face meeting, the data relating to each question were critically discussed and comparisons were made between the findings for each question, to identify overlaps and relationships about how PARIHS has been used.
After duplicate control, 1613 references remained. These were sorted by language and type of publication. In this phase, 131 references categorized as books, book chapters, conference proceedings, and publications written in non-English language were excluded. Also, three of the four core articles (i.e., the three citing Kitson et al.  which was the starting point for development of the PARIHS framework and therefore did not appear in the citation search) were excluded from the database [8, 9, 18], as were four articles expanding and refining PARIHS [19,20,21,22]. Accordingly, 1475 articles remained, and after the assessment excluding those merely citing PARIHS, a further 1108 articles were excluded, leaving 367 articles that cited one or more of the core articles, and made explicit use of the PARIHS framework (see Fig. 1 and Table 1).
Of these 367 articles, 235 cited Kitson et al. , 208 cited Kitson et al. , 136 cited Rycroft-Malone et al. , and 92 cited Rycroft-Malone et al. . In total, the 367 articles consisted of 35 protocols [25, 28, 29, 31,32,33,34,35,36,37,38, 40, 42, 44,45,46,47,48,49,50, 52,53,54, 56, 57]. A further 255 articles reported empirical studies:
▪ 91 where PARIHS guided the development of the intervention [58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, 145, 146, 386,387,388],
▪ 92 intervention studies where PARIHS did not guide the development of an intervention [149, 152, 153, 155, 156, 158, 160, 162, 167, 168, 171, 176, 178, 179, 182,183,184,185, 194, 201,202,203, 205,206,207,208,209, 211, 212, 214, 217, 219,220,221,222,223, 225, 234,235,236, 243,244,245, 249,250,251,252, 254, 255, 258,259,260,261, 263, 265, 266, 268,269,270, 273, 274, 276,277,278,279,280,281,282,283,284,285, 287,288,289,290,291,292, 296, 297, 299,300,301, 303,304,305,306,307,308,309,310,311,312],
▪ 72 non-intervention studies [150, 151, 154, 157, 159, 161, 163,164,165,166, 169, 170, 172,173,174,175, 177, 180, 181, 186,187,188,189,190,191,192,193, 195,196,197,198,199,200, 204, 210, 213, 215, 216, 218, 224, 226,227,228,229,230,231,232,233, 237,238,239,240,241,242, 246,247,248, 253, 256, 257, 262, 264, 267, 271, 272, 275, 286, 293,294,295, 298, 302]
In addition, the database included 28 empirical review studies [3, 13, 313, 314, 316,317,318,319,320,321,322,323,324,325,326,327,328,329,330,331,332,333,334,335,336,337,338, 389] and 49 opinion/theoretical articles [2, 144, 339,340,341,342,343,344,345,346,347,348,349,350,351,352,353,354,355,356,357,358,359,360,361,362,363,364,365,366,367,368,369,370,371,372,373,374,375,376,377,378,379,380,381,382,383,384,385]. In terms of professional focus, about 65% of the included articles involved nursing.
In the following sections, references have been added to the categorical items in the data extraction while we have opted only to provide examples of references to the findings from the qualitative exploration of how the PARIHS framework was operationalized in detail.
Of the articles reporting type of setting where the implementation project/research took place, a majority were undertaken in hospitals (n = 126) [26, 27, 30, 38, 39, 41, 42, 45, 49, 51,52,53,54,55, 60, 62,63,64, 67, 70,71,72, 77, 84, 85, 88, 89, 95,96,97,98, 103, 106, 107, 111, 115,116,117,118, 120,121,122, 128, 131, 132, 136, 137, 139, 143, 146, 149, 151, 153,154,155, 157, 161, 165, 167,168,169, 172, 173, 175, 180,181,182, 184, 186, 190,191,192,193, 205, 207, 212, 215, 221, 223, 227, 230, 231, 240, 243, 244, 246, 248,249,250,251, 256, 258, 260, 265, 268, 271, 273,274,275, 277,278,279, 281, 282, 284, 288,289,290, 294, 296, 298, 299, 301, 305, 306, 312, 314, 320, 336, 352, 353, 360, 362, 382, 386, 388], followed by a combination of multiple healthcare settings (n = 80) [31, 35, 37, 47, 50, 56, 65, 66, 68, 73, 79, 92, 99, 100, 109, 110, 112, 114, 133, 138, 144, 145, 150, 159, 160, 162, 163, 171, 177, 183, 187, 194, 197, 204, 208,209,210, 216, 218, 219, 226, 228, 233, 238, 245, 253, 262, 264, 276, 280, 283, 287, 292, 293, 295, 302, 307,308,309,310, 313, 321, 323, 326, 327, 329, 330, 333, 337, 338, 344, 345, 365, 367, 368, 371, 373, 376, 387, 389], community/social care settings (n = 54) [24, 34, 36, 43, 44, 46, 48, 57, 59, 61, 69, 74,75,76, 80, 81, 86, 87, 94, 102, 104, 108, 113, 123, 129, 134, 142, 152, 156, 158, 174, 178, 185, 195, 201, 203, 214, 217, 222, 229, 232, 241, 257, 263, 266, 269, 270, 300, 304, 351, 355, 357, 363], primary health care (n = 34) [23, 25, 28, 29, 40, 58, 82, 90, 93, 119, 125, 130, 140, 141, 164, 170, 196, 198, 200, 202, 224, 225, 235, 236, 242, 252, 259, 261, 272, 285, 286, 291, 332, 340], and home-based care (n = 7) [78, 91, 105, 166, 254, 255, 311]. Five articles were derived from special settings such as construction , education , pharmacies , urban planning , and public health institutions . In 44 articles [2, 3, 13, 33, 124, 126, 127, 179, 206, 211, 220, 237, 239, 247, 297, 316, 317, 322, 324, 325, 328, 339, 341,342,343, 346,347,348,349,350, 354, 356, 358, 364, 369, 372, 374, 375, 377, 378, 380, 381, 384, 385], the setting was not reported or not applicable (e.g., opinion/theoretical articles). For empirical studies and published protocols, about 28% were derived from research in the USA, 22% from Canada, 10% from Sweden, and 10% from the UK. The remaining articles mainly originated from other high-income countries in Europe; in addition, there were a few articles reporting studies in low- and middle-income countries, including Vietnam, Tanzania, Mozambique, and Uganda [46, 82, 110, 150, 235, 287].
Timing of different types of articles
The types of articles published using the PARIHS framework changed over time, with an increase in the number of empirical studies from 2004 onwards, as illustrated in Fig. 2. As the search for articles for this review only included the first eight months of 2019, the graph is limited to full years (i.e., 1998 through 2018).
Use of PARIHS
Figure 3 depicts how PARIHS was used by type of article. Although authors frequently claimed that PARIHS was used in one or more ways, details as to how the framework was used were often lacking.
The application of PARIHS to plan and deliver an intervention
In total, 117 (32%) articles claimed to use the PARIHS framework to plan and deliver an intervention [23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46, 58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, 145, 146, 339, 340, 386,387,388]. Predominantly, these were empirical studies (n = 91) [58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, 145, 146, 386,387,388] but also two opinion/theoretical articles [339, 340] and 24 protocols [23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46]. Of the 117 articles, about half stated that the framework was used for theoretically informing, framing, or guiding an intervention (e.g., [82, 103, 105, 134, 386]). However, in these studies, PARIHS was referred to only in a general sense, in that the core elements of the framework were said to have informed the planning of the study. There was a lack of detail provided about what elements of the framework were used and how they were operationalized to plan and deliver an intervention. In the other half of the 117 articles, it was described more specifically that one or more elements of the framework had been used. Most commonly the facilitation element (e.g., [58, 80, 92, 98, 110]) was referred to as guiding an implementation strategy. The articles that provided explicit descriptions of interventions using facilitation employed strategies such as education, reminders, audit-and-feedback, action learning, and evidence-based quality improvement, and roles including internal and external facilitators and improvement teams to enable the uptake of evidence (e.g., [23, 79, 125, 142]). Some articles drew on the PARIHS framework more specifically, to understand the role of organizational context in implementation (e.g., [34, 63, 145, 340]).
The application of PARIHS in data analysis
There were 184 (50%) articles where the PARIHS framework was reported to be used in the analysis [2, 13, 23,24,25,26,27,28,29,30,31,32,33,34,35, 47,48,49,50,51,52,53,54,55, 58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89,90,91,92,93,94, 149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242, 313, 314, 316,317,318,319,320,321,322, 339, 341,342,343,344,345,346,347,348,349,350,351,352,353,354,355,356,357,358, 386, 389]. Most of these involved empirical studies (n = 131) [58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89,90,91,92,93,94, 149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242, 386] where PARIHS often was described as guiding or framing the data collection, e.g., developing an interview guide, and/or analysis, but with no further details. In articles that provided more detailed information, PARIHS was used to guide or frame qualitative analyses in about 50 studies (e.g., [67, 94, 173, 178, 207]). Of these, around 20 used a deductive approach in that they used the elements and sub-elements to structure the analytic process (e.g., [150, 170, 188, 215, 242]). About 35 studies applied PARIHS for quantitative analysis, (e.g., [69, 168, 174, 190, 211]). In half of these, the Alberta Context Tool (e.g., [155, 165, 180, 195, 229]) and the Organizational Readiness to Change Assessment Tool (e.g., [74, 159, 219, 240]) were used; both these tools being derived from PARIHS. Empirical studies using the PARIHS framework in the analysis encompassed primarily all three main elements of PARIHS (e.g., [166, 181, 193, 221]) and the context domain (e.g., [78, 152, 153, 207]), and in lesser extent the evidence (e.g., [185, 208, 214]) and the facilitation domain (e.g., [58, 67, 79, 182]).
Eleven review studies [13, 313, 314, 316,317,318,319,320,321,322, 389] used the framework for the analysis; findings were mapped to PARIHS elements in a few studies [316, 317, 389]; one described that their data had been “analysed through the lens of PARIHS” (p1) . A couple of the review studies had PARIHS as the object for analysis, comparing it with other frameworks [318, 322]. This approach was also common in the 20 opinion/theoretical articles [2, 339, 341,342,343,344,345,346,347,348, 350,351,352,353,354,355,356,357,358], where the PARIHS framework itself was the focus of the analysis (e.g., [341, 349, 354]). In these articles, the analysis was performed in different ways, primarily through mapping and comparing PARIHS to other frameworks or models or even policies, but also for general discussions on implementation and evidence-based practice. Among the 185 articles that reported using the PARIHS framework in the analysis, there were also 22 protocols where authors reported that the intention was to use the framework in the analysis [23,24,25,26,27,28,29,30,31,32,33,34,35, 47,48,49,50,51,52,53,54,55].
The application of PARIHS in the evaluation of study findings
A total of 203 (55%) included articles provided information on how the PARIHS framework was used in the evaluation of study findings, in terms of contributing to the discussion and interpretation of results [13, 52, 58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89, 95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121, 149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214, 243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259, 261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280,281,282,283,284, 313, 314, 316,317,318,319,320, 323,324,325,326,327,328,329,330,331, 339, 341,342,343,344,345,346,347,348,349,350, 359,360,361,362,363,364,365, 386, 389]. The majority (n = 167) of these were empirical studies [52, 58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82, 84,85,86,87,88,89, 95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121, 149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214, 243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259, 261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280,281,282,283,284, 386].
We found two main approaches to how the PARIHS framework was used in the evaluation of study findings. First, PARIHS was used to organize the discussion of the findings (e.g., [73, 87, 109, 166, 214]), where the framework and/or its elements were used to provide a structure for reporting or generally discussing the findings, or both, for example in stating that the key elements of PARIHS were reflected in the study findings. Second, the framework was used to consider the implications of the study’s findings (e.g., [81, 84, 170, 207, 361]), where the framework or its elements (varying between one (e.g., [75, 195, 211]), two (e.g., [71, 86, 105]), and all the three main elements (e.g., [80,