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Ontario Medical Review
Dec. 23, 2020
Ontario Medical Association
Sharada Weir, DPhil; Kathleen Clements, MBA  Nadine Chami, PhD; Jasmin Kantarevic, PhD   OMA Economics, Policy & Research 

This article originally appeared in the November/December 2020 issue of the Ontario Medical Review magazine.

Healthcare evaluative research

Transforming Ontario’s health care system through original research on priority physician-identified issues

What do health and labour economics, biostatistics and data science have in common? They are powerful fields of research, beyond clinical medicine, that can be leveraged to inform and support Ontario’s doctors. This is one of the many areas that will be explored in this new series of OMR “Spotlight” articles highlighting the ongoing work of the five teams – Analytics; Economics and Survey Insights; Healthcare Evaluative Research; Research Group; and Tariff – that make up the OMA Economics, Research & Analytics (ERA) unit. 

As one of three units within the OMA Economics, Policy & Research Department (other units are Health Policy & Promotion, and Change Management & Implementation), ERA applies its teams’ extensive subject matter expertise, experience and analytical capabilities to over 20 terabytes of integrated claim and clinical data in order to:  

  • Support physician well-being  
  • Advance the role of physicians as leaders in transforming Ontario’s health care system 

This second edition of Spotlight on ERA will showcase the work of the Healthcare Evaluative Research Group.  

ERA Healthcare Evaluative Research Group 

Who we are 

The Healthcare Evaluative Research (HER) Group is a team of experienced researchers with advanced academic training in health and labour economics, biostatistics, and data science.  

What we do 

HER Group was formed to position the OMA as a thought leader and trusted voice in transforming Ontario’s health care system through its original research on priority issues affecting physicians and their patients. Our objective is to elevate the physician voice in the system through the production and wide dissemination of rigorous, peer-reviewed research.  

We use OMA database holdings, surveys, and other sources of information to address issues pertinent to OMA members and the population of Ontario. We publish original health economics and health services research studies on a wide range of topics with a particular focus on health care access, quality and costs. 


Patient complexity 

Examining a patient’s diagnosis history can reveal a great deal about their clinical complexity and costs of care. In fact, prior diagnoses can be used to predict future health care costs for the population or for specific groups of patients, such as patients rostered to a particular physician group or patients living in a particular geographic area. With this in mind, the HER Group set out to become leading experts in the methodology used to determine patient cost risk.  

HER Group has published the first-ever studies externally validating the Canadian Institute for Health Information Population Grouping Methodology for use in predicting current and future period costs and identifying patients who are likely to become high-cost health-care users.3 Moreover, using CIHI’s health condition grouping methodology, we were able to provide a more complete picture of chronic disease prevalence and multi-morbidity in Ontario than prior studies.4 

Figure 1 shows the increase in number of patients with chronic conditions and multimorbidity over the most recent 10-year period for which data are available. Our analysis suggests that the increase in chronic disease is only partly explained by population aging. 


Practical significance to OMA members: Our findings indicate that the burden on the health care system is growing. This research has implications for physician workforce planning, and this information will help to inform the OMA’s negotiations on behalf of physicians. 

Gender pay gap 

The gender pay gap in medicine has been identified as a key priority for the OMA. Economics, Policy & Research (EPR) staff have begun to explore the gender pay gap, and conducted a theoretical review, international literature review, and original research using the OMA’s administrative data holdings. The work was supplemented by consultations with members and leading academic researchers with relevant subject matter expertise. Following release of the Gender Pay Gap report,5 EPR staff conducted separate surveys of Council Delegates and the Membership at large to gauge member attitudes toward the GPG in medicine, to explore beliefs surrounding the perceived causes and remedies of this gap, and to guide future research exploring potential causes and remedies. 

Practical significance to OMA members: HER Group examined average daily OHIP billings and payments in FY 2017-18 and found that, on days when physicians billed or shadow billed for services rendered, female physicians earned 77 cents to the dollar earned by male physicians(see Figure 2). To put it another way, this corresponds to an unadjusted billings gap between male and female daily billings of 22.5 per cent. Even after accounting for working characteristics, geography, and OHIP specialty, the remaining unexplained gap was 13.5 per cent, which means that female earnings would need to increase by 15.6 per cent to close the gap (see Figure 3). Work is currently underway to better understand the causes of the unexplained pay gap, including possible gender biases in referrals.  



Graph showing that female earnings would need to increase by 15.6% to close the gender billing gap.

The OMA’s report is the first Canadian study to comprehensively examine a physician population for evidence of a gender pay gap.

Laboratory diagnostic test interventions  

The HER team recently published a study that examined how strict and soft policy interventions to optimize laboratory utilization influenced physician ordering behaviour.7 Between December 2010 and January 2013, the Ontario Ministry of Health implemented strict and soft policy interventions targeted at improving laboratory utilization management for certain laboratory tests in Ontario. A soft policy intervention was defined by the removal of laboratory tests from the tick box section of the requisition form, while strict policy interventions included the restriction of certain tests to only specific health conditions or the restriction of test ordering to certain physician specialties. Soft policies were found to be associated with an 8-36% reduction in laboratory testing for ferritin, thyroid stimulating hormone (TSH), vitamin B12, chloride, and creatine. Strict policy interventions were found to be associated with a 16-75% reduction in laboratory testing for vitamin D, folate, and serum glutamic-oxaloacetic transaminase (aspartate aminotransferase) (SGOT(AST)). An example is illustrated in Figure 4 for 25-hydroxy vitamin D testing, which shows a 73% reduction in testing upon the introduction of a condition-specific restriction in testing in December 2010. 

Graph showing a 73% reduction in testing of 25-hydroxy vitamin D

Practical significance to OMA members: Our findings indicate that the application of health policy interventions in Ontario – either soft or strict – can be effective at encouraging appropriate laboratory utilization practices. Showing that even soft policies were effective may encourage the Ministry to preserve physician discretion wherever possible in future policy development.