PASS 2020 Update

Use the button(s) below to download the PASS 2020 installation file. If PASS 2020 is not yet installed on your computer, this will install the full version. If you already have PASS 2020 installed, this will update your current installation to the newest version. Your personal files will not be affected.

PASS 2020 Download

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File: PASS2020Setup_v20_0_5.exe
Size: 223.12 MB
Current Version: 20.0.5
Released: February 19, 2021

Click here for minimum System Requirements

Documentation

PDF documentation for PASS 2020 is installed with the software and can be accessed through the Help System. The documentation is not available online at this time.

Update Release Notes

This page lists the changes that have been made to PASS 2020 since it was released.

Version: 20.0.5

Released: February 19, 2021

1. Minor documentation updates.

2. Corrected an error in the Logrank Tests procedure. When using Mortality input, power and sample size were not computed correctly when entering M1 (Mortality - Control) and MR (Mortality Ratio = M2/M1). Power and sample size were correct when entering M1 (Mortality - Control) and M2 (Mortality - Treatment).

3. Corrected “Unhandled exception…” errors that occurred when opening PASS procedures in Windows 10 when the Microsoft Region language option Beta: Use Unicode UTF-8 for worldwide language support is active. (To determine if the option is active on your computer, see the steps below.)

Having the Beta: Use Unicode UTF-8 for worldwide language support option active may lead to other errors. We recommend that the option be disabled when using PASS.

To disable this option in Windows 10, perform the following steps with administrator rights on your computer:

a. Close all open documents and programs on your computer.
b. Press the Windows key.
c. Type “Settings.”
d. Select Time & Language.
e. Click Language.
f. Under Related settings, click Administrative language settings.
g. On the Region window, click the Administrative tab.
h. Click Change system locale. (Here you will need administrator rights.)
i. Clear the Beta: Use Unicode UTF-8 for worldwide language support checkbox.
j. Click OK.
k. Restart your computer.

Version: 20.0.4

Released: January 28, 2021

1. Corrected an error in the two Mendelian Randomization procedures that caused the reported value for N when searching for sample size to be off by 1 in some cases.

2. Corrected an error in the Tests for Two Ordered Categorical Variables procedure. The software was not displaying the Group 2 Proportion values correctly (it was displaying all zeros for P2. The error did not affect calculations.

3. Corrected fatal errors that were occurring when editing lines, colors, and symbols in Group-Sequential Boundary Plots.

4. General startup stability improvements.

Version: 20.0.3

Released: August 27, 2020

1. Mediation procedures have been corrected to allow for negative value input in all appropriate cases. Before the corrections were made, the sample size search would not converge.

2. Corrected a “value out of range” error that was occurring in the Confidence Intervals for One Proportion in a Stratified Cluster-Randomized Design procedure in some cases when the computer language setting uses comma as the decimal.

3. Corrected an error in the display of input headings for the One-Sample Logrank Tests procedure. The "Alpha" heading was being displayed in error on the panel when the Solve For was set to "Effect Size".

4. Corrected output typos in the two-sided null hypothesis for the Two-Sample T-Tests Assuming Equal Variance procedure, Two-Sample T-Tests Allowing Unequal Variance procedure, and the Mann-Whitney U or Wilcoxon Rank-Sum Tests. The null hypothesis for the two-sided test was incorrectly stated as H0: δ ≠ 0 instead of H0: δ = 0. This error did not affect calculations.

Version: 20.0.2

Released: May 22, 2020

1. Updated the Tests for Two Ordered Categorical Variables procedure to include Odds Ratio input (in addition to Log(Odds Ratio) input) and additional methods for specifying the control group category proportions.

2. Added examples to demonstrate how the Tests for Two Ordered Categorical Variables procedure can be used in planning a clinical trial to assess the effectiveness of a treatment in combatting COVID-19 where the study outcome is based on a multi-category ordinal scale of illness severity.

3. Added an example to demonstrate how the Logrank Tests (Freedman) procedure can be used in planning a clinical trial to assess the effectiveness of a treatment in combatting COVID-19 where the study outcome in each group is the number of days it takes patients to advance two categories on a multi-point ordinal scale of disease status.

4. Corrected an error in the Equivalence Tests for the Ratio of Two Means (Normal Data) procedure. The values of N2 and N were displayed wrong in some cases. Incidentally, N2 is not used in the power calculation, so that value is correct.

5. Corrected an error in the Group-Sequential simulation procedures that required the user to repeatedly press “Abort” in order to Abort a procedure run.

6. Corrected an error in the Cox Regression procedure when solving for power with B = 0. PASS was returning Beta for Power instead of returning Alpha for Power.

7. Corrected an error that caused plots with Extra Symbols added outside the bounds of the plot lines to become tiny. Extra symbols outside of the plot boundaries are not displayed.

8. The validation example (based on Lakatos, 1988) for the Two-Group Survival Comparison Tests (Simulation) procedure and the Logrank Tests procedure had the noncompliance and drop-in rates reversed. This was fixed in the documentation and in the validation example templates. The fix did not result in a change to the estimated sample size.

9. Corrected minor typos in the power formula in the documentation of the Equivalence Tests for the Difference Between Two Correlated Proportions procedure.

Version: 20.0.1

Released: February 10, 2020

1. Initial Release of PASS 2020.

"PASS is a great program. It does so much and is easy to use. It’s much better than the other sample size programs I’ve used—it has helped me greatly in my research."

Ken Lawson, Ph.D., The University of Texas

I have been using NCSS in my high school class room for 22 years. I find it very easy to use and my students use it to calculate their results for their lab reports, science fair projects, and now they are using it for AP Research projects. It can be used for everything from the basics to the most advanced statistics. NCSS is very affordable for any high school budget.

David Buncher, High School Teacher, Miami, FL