Doubting of NP abilities prompts groundbreaking research

18 April 2014

A debate over the reasoning skills of nurse practitioners prompted groundbreaking research indicating NPs diagnostic skills are just as good as doctors.

Nurse practitioner Alison Pirret says she compared the diagnostic reasoning of 30 nurse practitioners with 16 trainee medical specialists (registrars) for her PhD research and found no difference (see scenario and details below).

The nurse practitioner role, long established in the United States and in New Zealand since 2001, involves nurse practitioners diagnosing and prescribing in their scope of practice. 

Pirret, who is also a lecturer at Massey University’s Albany campus, says there was reluctance by some employers to employ NPs and also some debate about NPs' reasoning abilities to do the job, particularly for complex cases requiring a lot of thinking and knowledge to work out the diagnosis”.

This debate was in part triggered by articles published by Health Workforce New Zealand executive chair Professor Des Gorman (who is also head of the school of medicine at the University of Auckland) about generic doctor ‘attributes’ and his suggestion of different cognitive thinking skills between doctors and other health professionals.

An article in 2009 in the Journal of Primary Health Care took up the debate with nurse practitioners Mary Jo Gilmer and Mark Smith arguing the affirmative that NPs provided a “substantive opportunity for task substitution in primary care” and Professor Gorman arguing the negative including nurses “apparent reluctance to accept roles that result in significant clinical responsibility”.

Pirret is New Zealand’s 26th NP and has been an intensive care NP at Middlemore Hospital since 2007.

She said there while there was international research showing NPs managed chronic conditions and minor illness and injuries as well as doctors there was no research on their management of complex cases presenting for the first time.

“The risk was we could have come out poorly and I felt a huge responsibility doing this study."  Her research (see below) used a complex case scenario based on a real person with the potential for multiple diagnoses as well as a questionnaire to find out what maxims were used when determining diagnoses and planning care.

A difference she did find was that although nurse practitioners practiced independently and autonomously they had built relationships with medical specialists and were far more likely to consult than the registrars.

"Nurse practitioners have often been criticised for being independent and autonomous, however, they can manage these more complex patients presenting for the first time and when these patients exceed their abilities to manage independently they readily collaborate with their medical colleagues and have developed those relationships to do so."

Dr Pirret believes many doctors have felt threatened by nurse practitioners as they can get Ministry of Health funding for seeing patients that have previously been given to doctors.

She concludes her thesis by saying her findings support the NP role as a “sustainable solution firstly, to effectively meet the health needs of the New Zealand population and secondly, to address workforce shortages.”

Health Workforce New Zealand and Gorman’s championing of the piloting of physician assistants to work in primary health care and acute care has also caused concern amongst nursing leaders who believe the nurse practitioner role is being sidelined.


A 67-year-old man who has two-week history of flu-like illness, backache, posterior chest pain and cough.  He visited his GP one week ago and was prescribed amoxicillin 500g three times daily but no improvement.  Brought into out-of-hours medical centre by daughter with complaints of worsening cough and left-sided chest pain.

The scenario supplies a summary of his health history – including type 2 diabetes, - his current medications, family history, lifestyle, physical examination results, x-rays and lab test results.

The research participants were given one hour to complete the case scenario and asked to “think out aloud” their thinking and diagnostic processes.

An expert panel determined the correct diagnoses/problems and actions for the case scenario using a Delphi technique.

There was no statistical difference between the mean number of correct diagnoses between the NPs and the registrars (mean of 10.3 correct diagnoses for NPs and mean of 10.88 for the registrars)/

The research also found that diagnostic reasoning style was not related to diagnostic reasoning abilities in either the nurse practitioner or registrar groups.