Before evaluating an NPI, it is essential to describe it. Sometimes, health practices may involve a combination of diagnostic methods and treatments, as seen in osteopathy. An NPI is not intended to identify or diagnose a health problem; rather, it serves as a preventive or therapeutic solution to address it, sometimes in conjunction with other treatments. A common confusion lies in distinguishing between an NPI and an approach or technique. An approach is too vague and does not accurately describe the content of the NPI, while a technique is too specific, representing only one ingredient of an NPI. A prototypical study allows for the comprehensive description of all characteristics of an NPI, including its health objectives, target population, mechanisms of action, content, implementation context, and the prerequisites for the professional involved.

An evidence-based data point is a theoretical or practical knowledge acquired through rigorous and integrated scientific methods and reasoning. The NPIS Model follows this logic in the health field (see Figure 3). It provides specific methodological and ethical recommendations for NPI for studies focusing on their mechanisms and explanatory processes (mechanistic study), their content (prototypical study), their evolution over time (observational study), their benefits and risks (interventional study), and their application and personalization modalities (implementation study).

NPI are protocols to be implemented with a target population, but they are merely specifications. They must be contextualized and personalized. The NPI Registry offers best practices and tips for optimal implementation. Furthermore, the NPIS recommends interdisciplinary training in health ethics for their application. The scientific society works with its partners to develop and recognize this foundational training, which could be conducted particularly in higher education institutions in collaboration with the Ministry of Health. This ethical training includes all the prerequisites of knowledge, skills, and attitudes necessary for interprofessional practice in health. Health professionals with practical experience, such as doctors, will have equivalencies.

If a clinical trial demonstrates the effectiveness of an NPI in one country, it does not necessarily mean that the health prevention or care protocol is equally relevant, feasible, or acceptable in another. Therefore, the NPIS Model recommends conducting an implementation study to identify the conditions for implementing the NPI in a specific health territory or country, ensuring that best practices respect local culture, habits, customs, and individual preferences.

The choice and implementation of an NPI at a given moment in a person's prevention and care journey do not depend on the NPI Registry, nor on the mission of the NPIS. These decisions are influenced by individual health situations, preferences, the availability of professionals, the qualifications of practitioners, accessibility in a given area, and socio-cultural contexts. The art of combining NPI with each other and with other health solutions at the right time lies with professionals, expert systems, interdisciplinary organizations, and the healthcare system in place in a specific country. The NPI Registry highlights essential practices that have proven effective and continue to evolve through research and feedback analysis. The NPIS has no authority to impose a choice of NPI. Each professional is free to follow them, to pursue others, or to create new ones. The same applies to each healthcare organization.

As of April 2019, there were 46 evaluation models for NPI in the scientific literature (Carbonnel and Ninot, 2019). These models were constructed by researchers for researchers, often from a monodisciplinary perspective and rarely from a patient-centered approach. This led to significant heterogeneity in study protocols and the way NPI were conceived (approach, method, technique, or materials). The results were scattered, debatable, poorly transferable, and rarely reproducible. Consequently, these practices were not widely recognized outside the study context (dependent on the establishment and/or practitioner). This situation raised doubts about their effectiveness (e.g., efficacy, safety, relevance, utility, cost-effectiveness), their content (e.g., heterogeneity in doses, procedures, ingredients, techniques, contexts, target populations), their approval (e.g., ethics committees), their dissemination (e.g., conflicting reviewer opinions), their teaching (e.g., protocols, best practices), and their recognition (e.g., authorization, integration into official classifications, reimbursement). This lack of a consensual evaluation model for NPI suggested that each professional had to reinvent their program for every new patient, given the wide or contradictory recommendations from authorities, agencies, and scientific societies. It also implied that only the patient-provider relationship mattered in the health effects induced (Ninot, 2020). Moreover, it left the door open for pseudoscientific practices and, more broadly, parallel medicine, along with all the obscurantist, health-related, sectarian, political, and judicial issues that are known in France (Miviludes, 2022; CNOI, 2023; CNOM, 2023) and around the world (Ernst and Smith, 2018). This idea was also gaining traction in the United States in the field of oncology, aiming to juxtapose two medical offerings: one based on experimental science, primarily focused on surgery, medication, radiotherapy, and medical devices, and the other described as "complementary, integrative, or traditional," based on individual experience, opinions, and traditions (Mao et al., 2022). This second offering claimed exclusivity in the domains of prevention and care, emphasizing care for the person versus cure for the disease. Thus, the NPIS Model was co-constructed with the idea that experimental science could demonstrate the existence of effective, safe, and reproducible prevention and care protocols. This work was supported by seed funding for participatory research from INSERM and involved over 1,000 participants under the guidance of a committee of 22 multidisciplinary experts, including two user representatives. This transdisciplinary innovation is currently supported by 30 French scientific societies, the National Center for Palliative Care and End of Life, INCa, and the French Platform for Clinical Research Networks.