PASS 16 Update

Use the button(s) below to download the PASS 16 installation file. If PASS 16 is not yet installed on your computer, this will install the full version. If you already have PASS 16 installed, this will update your current installation to the newest version. Your personal files will not be affected.

PASS 16 Download

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File: PASS16Setup_v16_0_9.exe
Size: 147.68 MB
Current Version: 16.0.9
Released: August 27, 2020

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PDF documentation for PASS 16 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 16 since it was released.

Version: 16.0.9

Released: August 27, 2020

1. 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".

Version: 16.0.8

Released: May 22, 2020

1. 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.

2. 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.

3. 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.

Version: 16.0.7

Released: February 10, 2020

1. An error in the Mixed Models Tests for Two Proportions in a 3-Level Hierarchical Design (Level-3 Randomization) procedure was corrected. The input screen was not working properly when Solve For was set to “M.”

2. An error in the Mixed Models Tests for Two Means in a 2-Level Hierarchical Design (Level-2 Randomization) procedure was corrected. The error occurred when a search for “M” was run. M and power were correct, but K2 and N2 were not.

3. Fixed errors in the Equivalence Tests for Two Means (Simulation) and Equivalence Tests for Paired Means (Simulation) procedures. When using symmetric equivalence limits and multiple values for M1, only the first scenario had symmetric limits.

4. Corrected a typo in the formula for Power using W5 on page 437-4 of the documentation of the Tests for the Ratio of Two Poisson Rates procedure. The formula incorrectly indicated that Power(W5) = 1 - φ(…). It has been corrected to Power(W5) = φ(…) so that it matches what is actually being calculated. This typo did not affect the calculated results of the procedure.

Version: 16.0.6

Released: October 25, 2019

1. Corrected an error in the calculation of Power when solving for Sample Size in the Reliability Demonstration Tests of One Proportion with Adverse Events procedure. Type II Error (Beta) was being reported instead of Power. This has been corrected. Note that when solving for Alpha, the correct Power was reported.

2. Corrected a minor typo in the documentation for the Tests for One Proportion procedure related to the value of c in the power formulas for the continuity-corrected tests.

Version: 16.0.5

Released: May 23, 2019

1. Fixed a “Subscript out of range” error in the Tests for Two Proportions in a Repeated Measures Design procedure that occurred when Group Allocation was set to “Enter total sample size and percentage in Group 1” and Definitions were being output in the report.

2. Corrected a summary statement error in the One-Sample Logrank Tests procedure. The wrong value was being reported for “proportion surviving in the historic control group” in the summary statement when Input Type = S0, HR. This error did not affect actual calculations nor results displayed in the Numeric Results table.

3. Corrected an error in the Equivalence Tests for the Ratio of Two Poisson Rates and Equivalence Tests for the Ratio of Two Negative Binomial Rates procedures. When 1/RL was entered for RU (or 1/RU was entered for RL), the output would always report RU as 1.25 (or RL as 0.8). The correct values for RU (or RL) were used in calculations so the reported sample sizes and power values were correct. Only the reported value for the upper or lower bound was incorrect. This has been fixed so that the reported values for RU (or RL) match the actual values used in calculations.

4. Corrected an error in the Multiple Two-Sample T-Tests procedure when testing with unequal variances. The df was calculated incorrectly, which affected power only slightly.

5. Minor documentation changes to correct typos.

Version: 16.0.4

Released: November 2, 2018

1. Fixed power calculation error in the Tests for Two Correlated Proportions in a Matched Case-Control Design procedure. The author of the paper on which this procedure is based discovered a calculation error in his results. The calculations in PASS have been updated to reflect the author’s corrections.

2. Fixed power calculation error in the Tests for Two Variances procedure. The power was not being calculated correctly in some cases when the group sample sizes are unequal.

3. Fixed documentation typos in the Non-Central Chi-Square Distribution in the Probability Calculator documentation.

Version: 16.0.3

Released: August 17, 2018

1. Corrected issues encountered in various procedures where the period is used in a way other than to represent a decimal symbol (e.g. in “D0.L”) when the computer language uses a comma as the decimal symbol. The period was incorrectly being replaced by a comma in non-numeric instances.

Version: 16.0.2

Released: July 6, 2018

1. Corrected a rare error in the Stepped-Wedge Design procedures. Fringe models with no real solution were reporting power of 1 when the power should have been returned as missing with no solution.

2. Corrected an error in the Multiple Contrasts (Simulation) procedure. When solving for Sample Size, the target power value was being set to 1-(User-Entered Value for Power). The correct input power value is now used.

3. The Tests for Multiple Correlated Proportions procedure has been corrected to indicate that the procedure calculates power for the McNemar-Bowker Test of Symmetry, not the Stuart-Maxwell Test of Marginal Homogeneity. After further research, we have determined that Chow, Shao, Wang, and Lokhnygina (2018) incorrectly refers to the McNemar-Bowker Test as the Stuart-Maxwell Test. The Stuart-Maxwell Test is used for testing marginal homogeneity, utilizes a different and more complicated test statistic, and has no known closed-form sample size calculation method. The McNemar-Bowker Test (the test for which power is computed in the Tests for Multiple Correlated Proportions procedure) is used for testing paired table symmetry. While it’s true that symmetry implies marginal homogeneity (see Fagerland, Lydersen, and Laake (2017)), the power and sample size calculations for the McNemar-Bowker Test do not necessarily extend to the Stuart-Maxwell Test.

4. Corrected an error that caused incorrect power and sample size calculations when entering “R1” in the Tests for Two Proportions in a Stratified Design (Cochran/Mantel-Haenszel Test) procedure when the computer’s system language setting was set to a South African language setting or any other language setting where R is a currency symbol.

5. Corrected a “Subscript out of Range” error in Hotelling’s One-Sample T2 procedure that occurred when the language setting on the machine uses a comma as the decimal.

6. Corrected an error that occurred for some procedures when Autosave Procedure Settings is active. If an invalid filename character was in the procedure name (e.g. “/”), the user would be asked to create a new directory with every run.

7. Fixed various documentation typos.

Version: 16.0.1

Released: June 6, 2018

1. Initial Release of PASS 16.

NCSS is an excellent tool for clinical and epidemiological research that is both user friendly and economical with excellent support. It removes the "fear of statistics" from clinical research and makes research accessible to all curious clinicians.

Ted Rosenberg, MD MSc. FRCP(C), Clinical Assistant Professor, University of British Columbia

I have used several statistics tools, but NCSS is the best statistics tool. It is easy to use because the interface and menu are easy to be used. And NCSS is very useful to support an analysis [in] data research.

Evi Triandini, Researcher