Patient Reported Experiences and Outcomes of Safety in Primary Care (PREOS-PC)


The PREOS-PC is a patient / service user self-complete questionnaire which is designed to comprehensively measure experiences and outcomes related to patient safety in the primary care/ambulatory setting.


Current tools measuring patient safety rely on information provided by healthcare providers. However, evidence suggests that patients can recognise problems in health care delivery that are not identified by current systems of health care monitoring.

Developed with the support of the National Institute for Health Research (NIHR), the PREOS-PC is designed to be a comprehensive collection of information about the patient experience and patient safety problems within primary care.

The PREOS-PC consists of three versions; a short form, a compact form, and a comprehensive version, all of which can be used independently to assess five domains of patient safety in primary care in unique ways. It was developed by experts assisted by patient input and is valid for use in primary care.

·       The comprehensive form provides a comprehensive overview of patient safety while offering the best metric properties, whether for research or for the routine in-depth evaluation of service delivery.

·       The compact form offers a balance of both high psychometric standards and reduced administrative burden, facilitating its implementation and use in actual practice.

·       The PREOS-PC Screen offers a succinct summary of patient perception of safety that can be embedded in broader audits and evaluations of service delivery, ensuring adequate coverage of key domains.

The measure

A conceptual framework was developed for the PREOS-PC based on three necessary elements for patient safety events:

1.       Patient interaction with the health care system, including self-management

2.       Standards of care

3.       Actual or potential harm to patients


The PREOS-PC consists of 5 domains:

·       Practice Activation (the degree to which practices are perceived to be engaging in promoting safety)

·       Patient Activation (the degree to which the patient engaged in promoting safety)

·       Patients’ experiences of safety problems Impact on Health

·       Patient safety outcomes (harm)

·       General perceptions of safety

The measure has been shown to have good content and face validity and be acceptable to patients.

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What the PREOS-PC measure provides

·         A comprehensive collection of information about patients’ experiences and outcomes of patient safety problems in primary care.

·         Discrimination between different levels of patient safety between practices and over time.

·         Independent usage of different versions, depending on desired degree of granularity.


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We used state of the art methods for questionnaire development, following a mix-methods approach that combined qualitative and quantitative research methods.

1) Item generation: In order to ensure that PREOS-PC contains all relevant aspects of patient safety in the primary care setting, we conducted three discrete pieces of research: A systematic literature review for available instruments measuring patient reported experiences and/or outcomes of patient safety in primary care, a meta-synthesis of qualitative studies examining patients’ experiences of safety in primary care, and four focus groups with patients to identify domains and themes related to patient safety in primary care.

2) Questionnaire development: We started developing the questionnaire by identifying all the relevant items from the previously identified instruments and selecting the best candidates for inclusion in the new tool. Through an iterative process, we reviewed the selected items and introduced new items, and/or modifications to the items and/or the response scales. The development of the questionnaire was informed by the results of the qualitative researches (meta-synthesis and focus groups), and by the feedback from our Expert Panel and from multiple cognitive interviews with members of the public.

3) Pilot-test: We conducted a two-stage pilot-test that involved around 10,000 patients from 55 practices across England. Results from this pilot-test allowed us to examine the psychometric properties of the instrument and the feasibility of different administration methods.

4) Development of suite of measures: We conducted further psychometric analyses using Classical Test Theory and Item Response Theory for developing two shorter versions of the original PREOS-PC instrument (PREOS-PC Comprehensive): PREOS-PC Compact and PREOS-PC Screen.

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Administration Methods

The PREOS-PC is to date validated for pen and paper completion. Careful migration to a digital delivery format (for example screen based device) can be authorised. Please contact us for advice.

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