Time needed to treat calculator

Time needed to treat calculator
Introduction

“There is a significant gap between the expectations placed on healthcare professionals and the time they have to provide the expected care. This massive gap contributes to inefficiency in healthcare because we do not dedicate time to the most beneficial interventions. It also contributes to inequality in healthcare because we do not devote our time to patients who need care the most. Finally, it is a source of moral stress, moral injury, and professional burnout among clinicians.”

- Minna Johansson

Family Physician

Founder of the Cochrane Sustainable Healthcare Initiative

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All clinical actions require time, and the purpose of the calculator is not to question well-established medical practices with proven benefits. The calculator is designed to help you reflect on the time spent on low-value practices or to choose a less time-consuming approach when the benefits are similar between several options.

Visit the Global Center for Sustainable Healthcare's website for more information.
How to use the calculator ?

When the calculator asks for a number, assume the time is in minutes, and do not provide units or decimals or percentage symbols.
What test or treatment are you trying to calculate the ''time needed to treat'' for ?
There are three ways TNT can be calculated
1. By using the percentage of your patients who have a specific condition or who would be eligible to receive a test or treatment (ideal for estimating TNT for screening).
2. By specifying how often you encounter a situation or perform an action on a monthly basis.
3. By using population-based parameters (ideal for planning a public health or large-scale intervention).
How would you like to estimate how many patients this would apply to in your practice ?

How many patients do you have in your roster ?
To what percentage of your patients does the recommendation apply ? (%)
How long does discussing / prescribing or doing the intervention take you with each patient, on average (minutes) ?
What is the percentage of test results that come back abnormal (%) ?
Estimates for common tests
How much time does discussing and planning follow-up for normal results take you on average (minutes) ?
How much time does discussing and planning follow-up for abnormal results take you on average (minutes) ?
Every how many years should the intervention be performed ?
For example, if the intervention is screening and should be done every year, put ''1'' ; if the intervention should be performed more than once a year, provide a decimal (e.g. 0,5 for screening every 6 months)
We estimate it would take you the following time (provided in hours) to perform this intervention one time, including time to manage normal and abnormal results for all your eligible patients, on a monthly basis :
We estimate it would take you the following time (provided in hours) to perform this intervention one time, including time to manage normal and abnormal results for all your eligible patients, on a yearly basis :
We estimate it would take you the following time (provided in hours) to perform this intervention over a 25 year period of time with the specified interval, including time to manage normal and abnormal results for all your eligible patients :

How many time do you perform or recommend this intervention per month, on average ?
How much time does the intervention take (prescribing the test or treatment, including discussing it and or performing it, if applicable) ?
If this is a test or a physical exam, on what percentage of occasions does it reveal something abnormal (%) ?
Leave this field empty if this does not apply / the intervention is not related to testing
Estimates for common tests
How long does managing normal results take you on average (minutes) ?
Leave this field empty if this does not apply / the intervention is not related to testing
How long does managing abnormal results take you on average (minutes) ?
Leave this field empty if this does not apply / the intervention is not related to testing
We estimate it would take you the following time (provided in hours) to perform this intervention every month, including time to manage normal and abnormal results :
We estimate it would take you the following time (provided in hours) to perform this intervention every year, including time to manage normal and abnormal results :
We estimate it would take you the following time (provided in hours) to perform this intervention over a 25 year period, including time to manage normal and abnormal results :

What is the population size ?
To what percentage of of the population does the recommendation apply ? (%)
If you have a direct number you would like to input, you can simply specify it in the ''Population size'' box, and write 100 % in the percentage of the population the recommendation applies to.
How long does discussing / prescribing or doing the intervention take with each patient, on average (minutes) ?
What is the percentage of test results that come back abnormal or call-back rate (%) ?
Estimates for common tests
How much time does discussing and planning follow-up for normal results take on average (minutes) ?
How much time does discussing and planning follow-up for abnormal results take on average (minutes) ?
Every how many years should screening be performed ?
If screening should be performed more than once a year, provide a decimal (e.g. 0,5 for screening every 6 months)
We estimate it would take the following time (provided in hours) to perform this intervention one time, including time to manage normal and abnormal results for all eligible patients :
We estimate it would take the following time (provided in hours) to perform this intervention over a 25 year period of time with the specified screening interval, including time to manage normal and abnormal results for all eligible patients :
We estimate implementing the measure, including time to manage normal and abnormal results for all eligible patients, requires this number of full-time clinicians every year, assuming a person works 40 hours per week, 48 weeks per year :

Reflecting on your "time needed to treat" (TNT) calculations can be a pivotal moment in your clinical practice. This exercise goes beyond numbers—it challenges us to think critically about the value and timing of the tests and treatments we recommend. How did your results compare to your expectations? Were there instances where you reconsidered the benefit of a specific intervention in relation to the time investment? Is there solid evidence to support the intervention? Reflecting on these questions, and considering potential harms, helps us align our clinical decisions with evidence-based practices, ultimately improving patient outcomes.

Importantly, the time saved through more intentional practice extends beyond your own. Every unnecessary test can draw on the time and energy of laboratory and radiology technicians, nurses, and specialists in diagnostic medicine. There are also material and environmental costs to consider: disposable tubes, chemical reagents, patient and sample transport, and energy use—all of which contribute to the healthcare system’s carbon footprint. And when low-value testing clogs the system, patients who might truly benefit can face delays in care. Imagine the cumulative effect if every clinician made similar decisions—each seemingly small choice can scale into significant system-wide impact.

As you process this, consider the principles of the Choosing Wisely campaign, which advocates for reducing unnecessary interventions and focusing on what truly benefits patients. Are there areas of your practice where you might streamline treatment or reconsider the timing of interventions? Access resources on Choosing Wisely Canada's website to guide your reflection.

Lastly, reflection is not just an intellectual exercise; it's an opportunity for professional growth. If you're a family physician, consider utilizing tools like the CFPC's Mainpro Linking Learning Exercises, where reflective practice can be tied to continuing professional development (CPD) credits. If you're a Quebec physician, this can be used to claim category ''B'' credits.

If you're a specialist, explore the Royal College for similar reflective learning tools to support your ongoing education.

This process can facilitate real change, helping you break down barriers to implementing insights gained from exercises like TNT. By downloading a PDF summary of your TNT calculations, you can use this as a concrete reference in future reflective exercises, ensuring that the insights gained today are put into practice in your future clinical decision-making.

Latest update : September 25th, 2025
Authors :
René Wittmer MD CCFP
Guylène Thériault MD CCFP

Translations :
French : René Wittmer MD CCFP
Spanish : Juan Erviti, Pharm D, PhD
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Time needed to treat calculator

How to use the calculator ?