Comparison

Preop Eval vs EBM Stats Calc

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Preop Eval

This app provides guidance for evaluating and preparing adult patients for non-cardiac surgery. It includes algorithms and resources on medication management, cardiac event timing, and preoperative testing, serving as both a reference and a teaching tool for medical professionals.

Highlights
  • Cardiac evaluation algorithm
  • Medication guidance (starting/stopping)
  • Surgery timing after cardiac events
  • Preoperative testing recommendations
  • Review for students and residents
  • Perioperative insulin management
Features
Read full description

Preop Eval organizes and presents much of the guidance that one needs in order to evaluate and prepare adult patients for non-cardiac surgery. It is based upon the guidelines on this topic from the American College of Cardiology, the European Society of Anaesthesiology, the American Society of Anesthesiologists, the Institute for Clinical Systems Improvement, the American College of Chest Physicians, and more (full references in the app). The app contains 1 algorithm and 3 resources: the cardiac evaluation algorithm, guidance on starting and stopping key medications in the perioperative period, guidance on timing of surgery after cardiac events, and guidance on preoperative testing. It also contains a review of preoperative evaluation mainly for students and residents. The app addresses such common questions as: - who needs bloodwork before surgery? - who needs an EKG or a CXR? - how do I handle patients on warfarin, clopidogrel, and DOAC's? - which patients need adjustment of perioperative insulin and diabetic meds, and how? - which active cardiac conditions preclude surgery? - how long after MI or stent should a patient wait before surgery? - are there adjustments to make on psych meds, rheumatologic meds, ACE's and ARB's? This app is written and intended for practicing physicians like internists, family physicians, and hospitalists; for resident physician trainees; and for medical students. In addition to being a reference, the algorithm is written to be a teaching tool by not just delivering an answer, but instead walking a physician through the evaluation process so that one learns that process along the way. As an educator and clinician, I am interested in feedback and I would be grateful for guidance on improving the tool.

About

EBM Stats Calc

This medical app assists clinicians and educators in performing complex calculations related to evidence-based medicine. It offers tools for calculating NNTs, diagnostic test utility, and understanding the impact of pretest probability on posttest results.

Highlights
  • Calculate Number Needed to Treat (NNT)
  • Calculate diagnostic test utility
  • Pretest to posttest probability conversion
  • Positive and Negative Predictive Value calculation
  • Interactive slider for pretest probability demonstration
  • Useful for clinicians, students, residents, and educators
Features
Read full description

Occasionally in medicine, we really need to "do the math". This app will help. EBM Stats Calc let's a clinician do calculations that are hard or impossible to do in one's head. A clinician can get NNT's (number needed to treat) from rates, percentages, or raw event and patient numbers. And a clinician can use sensitivity and specificity or likelihood ratios (LR+, LR-) to go from a pretest probability to posttest probability and positive predictive value and negative predictive value. Although these calculators themselves are somewhat novel for apps, the unique tool in this app is for educators. Students and residents have a hard time understanding how the utility of a test can vary with pretest probability. Instead of saying it in words and hoping they get it, now you can demonstrate it. A test might perform well, giving good PPV and NPV, when pretest probability is in a certain range. But slide that pretest probability up or down and see the diagnostic utility change with the numbers flying right before your eyes. The tool also shows a student that in many cases, an imprecise estimate of pretest probability doesn't much matter. Different doctors might judge a clinical case to suggest likelihood of disease (pretest probability) of 40%, 50%, or 60%. The slider tool shows that the differences may not matter, and the test in mind will render good clarity regardless of differing opinions on pretest probability. The app is written for clinicians, students, residents, and especially educators, in any discipline of medicine. As a clinician and educator myself, I would be grateful for feedback to make the tool better.

Screenshots

Preop Eval4 screens
EBM Stats Calc4 screens

Verdict

The call

The clearest difference is rating: Preop Eval at 5.0 against EBM Stats Calc's 4.5. Preop Eval also leads on update cadence (every 6 months vs every 14 months). EBM Stats Calc's advantage is review sentiment (100% vs 67%) and device support (3 vs 1). On price, ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Preop Eval holds the better App Store score, 5.0 against 4.5. Both are backed by a comparable volume of ratings — 2 and 2 respectively. Written reviews complicate that: 67% of Preop Eval's written reviews are positive against 100% of EBM Stats Calc's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Preop Eval ships an update every 6 months, EBM Stats Calc every 14 months. The most recent releases landed on September 30, 2026 and October 12, 2026 respectively.

Scorecard5 real differences · 5 level
Preop Eval versus EBM Stats Calc: the parameters behind the verdict, then further details
ParameterPreop EvalEBM Stats Calc
PriceFreeFree
Rating5.0 (2 ratings) — better4.5 (2 ratings)
Positive reviews66.7% of reviews100.0% of reviews — better
Number of ratings22
Update frequencyEvery 6 months — betterEvery 14 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.613.0 — better
Further details — not scored
Size15 MB1 MB
Age rating17+12+
DeveloperUnited Health Services, Inc.Joshua D. steinberg

Customer experience

Preop Eval

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews12 reviews
Positive66.7%
Neutral8.3%
Negative25.0%

EBM Stats Calc

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Preop Eval

No in-app purchases

None

EBM Stats Calc

No in-app purchases

Questions

Is Preop Eval free?
Preop Eval is free to download, with no in-app purchases.
Is EBM Stats Calc free?
EBM Stats Calc is free to download, with no in-app purchases.
Which has better reviews, Preop Eval or EBM Stats Calc?
Preop Eval is rated higher. Preop Eval averages 5.0 out of 5 from 2 ratings, while EBM Stats Calc averages 4.5 from 2 ratings.
Do Preop Eval or EBM Stats Calc have ads?
Neither Preop Eval nor EBM Stats Calc shows ads.
Which is updated more often, Preop Eval or EBM Stats Calc?
Preop Eval ships an update every 6 months, and EBM Stats Calc every 14 months. Most recently, Preop Eval was updated on September 30, 2026 and EBM Stats Calc on October 12, 2026.

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