Article Text

Determining the psychometric properties of a written test to assess safe dental practice
  1. Syed Akbar Abbas Zaidi1,
  2. Farnaz Ilyas2,
  3. Saman Hakeem2,
  4. Asher Feroze3,
  5. Shaur Sarfaraz4,
  6. Syeda Kausar Ali5
  1. 1Dental Education Department, Bahria University Medical and Dental College, Karachi, Pakistan
  2. 2Prosthodontics, Bahria University Medical and Dental College, Karachi, Pakistan
  3. 3Health Research Advisory Board, HealthRAB, Karachi, Pakistan
  4. 4Medical Education, Altamash Institute of Dental Medicine, Karachi, Pakistan
  5. 5Institute of Medical Education, Jinnah Sindh Medical University, Karachi, Pakistan
  1. Correspondence to Dr Syed Akbar Abbas Zaidi; akbrabbaszaidi{at}


Introduction Safe practice in medicine and dentistry has been a global priority area in which large knowledge gaps are present.

Patient safety strategies aim at preventing unintended damage to patients that can be caused by healthcare practitioners. One of the components of patient safety is safe clinical practice. Patient safety efforts will help in ensuring safe dental practice for early detection and limiting non-preventable errors.A valid and reliable instrument is required to assess the knowledge of dental students regarding patient safety.

Objective To determine the psychometric properties of a written test to assess safe dental practice in undergraduate dental students.

Material and methods A test comprising 42 multiple-choice questions of one-best type was administered to final year students (52) of a private dental college. Items were developed according to National Board of Medical Examiners item writing guidelines. The content of the test was determined in consultation with dental experts (either professor or associate professor). These experts had to assess each item on the test for language clarity as A: clear, B: ambiguous and relevance as 1: essential, 2: useful, not necessary, 3: not essential. Ethical approval was taken from the concerned dental college. Statistical analysis was done in SPSS V.25 in which descriptive analysis, item analysis and Cronbach’s alpha were measured.

Result The test scores had a reliability (calculated by Cronbach’s alpha) of 0.722 before and 0.855 after removing 15 items.

Conclusion A reliable and valid test was developed which will help to assess the knowledge of dental students regarding safe dental practice. This can guide medical educationist to develop or improve patient safety curriculum to ensure safe dental practice.

  • Patient safety
  • Safety culture
  • Medication safety
  • Diagnostic errors
  • Medical error, measurement/epidemiology

Data availability statement

All data relevant to the study are included in the article or uploaded as online supplemental information.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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  • Most of the questionnaire were either related to awareness or perception. Very little or none focused on the knowledge related to safe dental practice.


  • This study formulates a validated and reliable test questionnaire which will help in assessing the knowledge of dental students, graduates and practitioners.


  • Gathered information related to dental students’ knowledge will guide policy-maker and medical educationist related to increasing weightage of safe dental practice in BDS curriculum.


Safe practice in medicine and dentistry has been global priority area in which large knowledge gaps are present and where more knowledge should be contributed to improve patient safety and reducing harm.1

Patient safety strategies aim at preventing unintended damage to patients that can be caused by healthcare practitioners.1 There are various components of patient safety, of which safe clinical practice is a major and important component. Patient safety efforts will help ensure safe dental practice and early detection while limiting non-preventable errors. Given the complexity of healthcare systems, it is impossible to completely prevent the occurrence of errors, accidents or complications during the provision of dental or surgical treatment. There are many serious drugs and advanced technical appliances that dentists handle, which can harm a patient. It is evident, however, that dentists, the same as other healthcare professionals, have an ethical and legal obligation to protect the patients from harm in as much as reasonably possible.2 3

Effective pharmacological knowledge is important in every health-related field whether it is medicine or dentistry. Dentists deal with patients from all age groups and also with those who have comorbidities. Therapeutic regimens are constantly changing, pharmaceutical companies release new and similarly named drugs, and changes in patient demographics imply an increasingly aged patient population with comorbidities that require more than one medicine. Therefore, a consistent update of knowledge is needed in practice of dentistry.4 5

Other than pharmacological or drug errors, there are additional patient safety errors in dentistry. These include: (1) surgical/procedure errors as a result of performing the wrong procedure or surgery, injuring adjacent teeth or tissues, or leaving foreign objects in the patient’s mouth.6 7 (2) Anaesthesia complications such as administering the wrong type or dose of anaesthesia, failure to monitor the patient’s vital signs during the procedure or failing to properly manage any complications that arise.8–11 (3) Failure to obtain informed consent and prescribing errors resulting from failure to explain a treatment or procedure to a patient, including the potential risks and benefits, and obtain the patient’s consent to proceed or an error in the prescription itself.4 12–14 (4) Failure to follow proper infection control procedures, such as hand hygiene, sterilisation of instruments and wearing appropriate personal protective equipment, increasing the risk of infection transmission.15–17 (5) Diagnostic errors including misinterpreting X-rays or other diagnostic tests, failing to diagnose a condition or misdiagnosing a condition.18–20

WHO had introduced patient safety as multiprofessional approach in curriculum which was developed for teaching and learning of safe clinical practices.21 Internationally, patient safety is the formal part of medical and dental curriculum but in Pakistan it is still not part of formal curriculum.

No published literature was found about the level of knowledge regarding safe dental practice among dental students in Karachi. Most of the literature claims to assess awareness rather than knowledge related to patient safety. In the context of patient safety, awareness and knowledge are both important, but they play different roles. Awareness of patient safety refers to an understanding of the potential risks and dangers that patients may face while receiving healthcare. This includes understanding the importance of hand hygiene, proper medication administration, preventing falls and other key aspects of patient safety. Awareness of patient safety is important for all healthcare providers, as it helps to promote a culture of safety and encourages everyone to be vigilant in preventing errors and harm. Knowledge of patient safety, on the other hand, refers to the specific information and facts that are needed to ensure safe patient care. This includes understanding the best practices for medication safety, infection control, communication and teamwork, and other essential elements of patient safety. Knowledge of patient safety is particularly important for healthcare professionals who are directly involved in patient care, as it enables them to make informed decisions and take appropriate actions to prevent errors and harm.

Literature review was unable to identify a validated instrument or a test specific to patient safety in dental practice.5 Majority of questionnaires were related to patient safety perceptions or attitude. Since none of these instruments found in literature assessed the knowledge related to patient safety. A multiple-choice question (MCQ) test was developed as a first step.

The main objective was to determine the psychometric properties of a MCQs test to assess safe dental practice. It is expected that with the help of this validated test, assessment of knowledge related to safe dental practice will be more accurate. Information related to knowledge of dental student will eventually help in guiding the policy-maker to provide weightage to this component and support medical educationist to add patient safety as an integral component in the undergraduate dental curriculum.

Materials and methods

This study was conducted on all final year dental students (52) of a private dental college who were near their final professional exam. It is expected that final year students should have enough knowledge related to patient safety as they have gone through clinical clerkship.

Step1: Development of the test questions

Content of the test was based on common errors that occur in dental practice which affect patient safety. These were identified by the researcher through literature review and discussion with four dental experts who were involved in teaching dental students and practicing dentistry in the clinic. The aspects identified included swallowing dental instruments,6 7 complications of local anaesthesia,8–11 prescribing errors,4 12–14 nerve damage,22–26 infection control issues,15–17 failure to address significant comorbidities,27 28 diagnostic errors,18–20 hypersensitivity reaction29–32 and needle prick injuries.33–35

Item writing: The MCQs were written according to National Board of Medical Examiners item writing guidelines36 having four options with only one correct option. The technical review of the MCQ was done with the help of two expert medical educationists who had more than 5 years of experience and necessary qualification.

Content validity: The items were then reviewed by 10 experts who were either professors or associate professors. Of these, eight were experts in dentistry and were teaching final year students and also doing dental practice and two were medical educationists with at least 5-year experience. The experts were asked to rate each item on the test for relevance (1: essential, 2: useful, not necessary, 3: not essential) and clarity of language (A: clear, B: ambiguous) (table 1).

Table 1

Experts selection of items

Content validity index was calculated by grouping ratings, and items selected as essential and clear were considered using formula:(ne-N/2) (N/2)37 where ne: number of experts who select items as essential and clear, N: total number of experts. Poorly rated items with a CVI of below 60% were removed. Initially, the test had 50 MCQs but on the basis of expert review eight items were removed from the study and the final test of 42 items (online supplemental file 1: questionnaire) was used in the study. This test paper (online supplemental file 1: questionnaire) was administered on 10% of the sample size to check whether students are able to understand questions correctly and if this question paper is assessing students’ knowledge related to safe practices. It was observed that few questions required correction as those items were not clear. Modifications were made accordingly.

Supplemental material

Step 2: Administration of the test

After piloting, the final test was administered to the final year dental students of the dental college. The students were informed of the purpose of the study and written consent was taken (online supplemental file 2). They were informed that they were free to leave without any fear of repercussion. The test was conducted in the lecture hall of the respective dental college and students were given 60 min to solve the test. Thereafter, the response sheets were taken back from the students. Response sheets were scored through an optical scanner. The response key was confirmed by the researcher after it was entered in the software. Ten per cent of the response sheets were rechecked manually. Written feedback was taken from the students regarding the test and quality of items on a locally developed feedback form.

Supplemental material

The minimum passing marks were determined with consensus of the dental experts. The minimum passing marks were set at 60%. Each correct question was awarded 1 mark for selection of the correct answer and 0 for a wrong answer.

Scoring of each item was 1 mark for correct answer and 0 for wrong answer.

Data was entered into Excel and then imported into SPSS V.20 for analysis. Reliability was calculated by Cronbach’s alpha. Each item was analysed for difficulty index, discrimination index and point biserial. For significance, p value was considered equal to or less than 0.05. Item difficulty was measured by dividing individual item score/total no. of students (ie, 50). Items equal to or less than 0.44 were considered difficult while items equal to or more than 0.76 were considered easy and remaining between 0.45 and 0.75 were considered moderate.38–42 The discrimination index was calculated in which items having less than 0.20 were considered poor discriminator while item having more than 0.39 were considered strong discriminator and remaining 0.2–0.39 were considered moderate discriminators.38–42


Total 18 (42.85%) items were found to have a difficulty index of less than 0.44 and discrimination index less than 0.20 whereas 4 (0.095%) items had a difficulty index of more than 0.76 and remaining were moderate. Pearson correlation was calculated in which items having negative value or significant value less than 0.05 were considered poor.38 Total of 17 (40.47%) items showed poor correlation (>0.05 or negative Pearson correlation). Reliability was calculated using Cronbach’s alpha. There were a total of 18 (42.85%) items which showed poor overall reliability when deleted. Items having poor outcomes in three or more parameters were considered for deletion38–42 (table 2).

Table 2

Item analysis

So out of 18 items,there were total of 15 items (q6, q7, q9, q11, q12, q13, q15, q24, q25, q27, q28, q30, q35, q37, q42) which were deleted. Overall reliability increased from 0.713 to 0.846 after deletion of poor performing items (table 3).

Table 3

Reliability statistics


Studies show that 0.90 or above is acceptable for high stake, 0.80–0.89 for moderate, whereas 0.70–0.79 is acceptable for low stakes test. Current study results revealed that even before deleting the items’ reliability was adequate, that is, 0.722. After item analysis, 15 items were removed. Reliability of this test improved from 0.722 to 0.855 which is acceptable for an instrument.43 Initially test consisted of 42 MCQs items which was administrated on final year dental students. It may be assumed that deleting the questions from the test might have compromised the coverage of content in domains of patient safety. But there were an adequate number of questions to assess the knowledge of students which did not affect the content of domains.

A self-assessment baseline questionnaire developed by Walton et al claims to check knowledge related to patient safety. Many studies administered this questionnaire on dental students which showed most of the students categorising themselves having good to higher level of understanding and knowledge which contrasts with the current study’s result.44 This most probably might be because of WHO questionnaire’s self-assessment nature where participant evaluate themselves which can result in biasness. Whereas in current study, questionnaire is like an exam or test which provides actual information regarding knowledge of students related to patient safety.

A recent study done by Das et al45 focuses on cross-infection control in private dental practice in Karachi, Sindh. This study consists of 10 questions assesing only awareness related to cross infection. Psychometric properties of the questionnaire were not seen in the study.

Moreover, Two studies worked on psychometric properties of Safety Attitudes Questionnaire (SAQ) and Hospital Survey on Patient Safety Culture (HSOPS). First study on psychometric properties of SAQ provides a thorough overview of the SAQ and its uses in various industries. The psychometric properties and benchmarking data make it a valuable tool for organisations seeking to improve their safety culture, and the emerging research highlights the ongoing importance of monitoring and assessing safety attitudes.46 In second study, authors used a multilevel approach to assess the reliability and validity of the survey, examining both individual-level and group-level factors. It measures various aspects of patient safety culture, including communication, teamwork, leadership and organisational learning.47 Similarly, a comparison study on both questionnaires was done by Etchegaray JM and Thomas which discusses the similarities and differences between the two surveys in terms of their content, structure and psychometric properties. The SAQ focuses more on individual attitudes and perceptions, while the HSOPS emphasises organisational factors that influence patient safety. Overall, the study concludes that both the SAQ and HSOPS are useful tools for assessing safety culture in healthcare organisations. Like SAQ, our study questionnaire helps in assessing the individual-level issues, but this questionnaire’s main focus is individual knowledge of students rather than finding perception and awareness. Also, our study questionnaire can also be used in identifying the lacking in BDS curriculum indirectly identifying the academic level issues.48 All the above three studies’ main focus was perception and attitude towards patient safety culture rather than knowledge. Patient safety culture has its importance, but adequate knowledge related to patient safety and safe dental practice is also necessary in healthcare system.

However, the limitation is that this study was conducted in only one institute hence the results may not be generalisable across all dental students. The final 42-item test demonstrated adequate validity and acceptable reliability (0.722) for assessment of knowledge of patient safety among final year dental students in case of low stake scenario. But considering patient safety importance, its domain cannot be undermined and deemed as low stake scenario. This means that, our test consists of flawed items which was dealt by deleting the mentioned 15 items in this study. But by doing so, the number of questions was reduced to 27 items which were not enough. In addition, this study was conducted during COVID-19 pandemic, which might also have affected the results.


To the best of our knowledge, this is the first instrument that has been validated for assessment of knowledge of patient safety in dental students. After deletion of 15 items out of 42 items, reliability of the test was increased from 0.722 to 0.855 which is good enough for high stake scenarios.


  • This validated questionnaire should be administered in multiple institutes to assess the knowledge of dental students.

  • Flawed items should be modified or replaced by new items to increase the number of items and it should be tested again for further improvement of validity and reliability of test.

Data availability statement

All data relevant to the study are included in the article or uploaded as online supplemental information.

Ethics statements

Patient consent for publication

Ethics approval

This study involves human participants and was approved by Ethical Review Committee Bahria University Medical and Dental College-ERC 18/2021. Participants gave informed consent to participate in the study before taking part.


I would like to express my deepest appreciation to Dr. Syed Moyn Ali (Director Academic, Jinnah Sindh Medical University) & Dr. Zafar Abbas (Assistant Professor Oral Medicine, Dow International Dental College) who has provided invaluable support and assistance throughout this research. I would like to thank institute for supporting and allowing us to conduct our study in their institute.


Supplementary materials

  • Supplementary Data

    This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.


  • Contributors Each of the authors contributed significantly to the conception, design and execution of the research project, as well as the analysis and interpretation of the data. SAAZ (guarantor) was responsible for the conceptualisation, literature review, study design, data collection and drafting of the manuscript. FI contributed to the study design, data collection and analysis, and provided critical feedback on the manuscript. SH provided critical feedback on the manuscript and contributed to the interpretation of the results. AF contributed to the study design and data collection and provided critical feedback on the manuscript. SS provided substantial contributions to the statistical analysis and interpretation of the data. SKA was involved in the study design, provided overall guidance and knowledge throughout the research, and contributed to the interpretation of the results. All authors read and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Disclaimer Authors declare that they have no relevant or material financial interest that relate to the research.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.