The FREQ Procedure

requests tests and measures of classification agreement for square tables. The AGREE option provides McNemar’s test for tables and Bowker’s test of symmetry for square tables with more than two response categories. The AGREE option also produces the simple kappa coefficient, the weighted kappa coefficient, their asymptotic standard errors, and their confidence limits. When there are multiple strata, the AGREE option provides overall simple and weighted kappas as well as tests for equal kappas among strata. When there are multiple strata and two response categories, PROC FREQ computes Cochran’s test. See the section Tests and Measures of Agreement for details about these statistics.

If you specify the WT=FC option in parentheses following the AGREE option, PROC FREQ uses Fleiss-Cohen weights to compute the weighted kappa coefficient. By default, PROC FREQ uses Cicchetti-Allison weights. See the section Weighted Kappa Coefficient for details. You can specify the PRINTKWT option to display the kappa coefficient weights.

AGREE statistics are computed only for square tables, where the number of rows equals the number of columns. If your table is not square due to observations with zero weights, you can specify the ZEROS option in the WEIGHT statement to include these observations. For more details, see the section Tables with Zero Rows and Columns.

You can use the TEST statement to request asymptotic tests for the simple and weighted kappa coefficients. You can request exact p-values for the simple and weighted kappa coefficient tests, as well as for McNemar’s test, by specifying the corresponding options in the EXACT statement. See the section Exact Statistics for more information.

requests all of the tests and measures that are computed by the CHISQ, MEASURES, and CMH options. The number of CMH statistics computed can be controlled by the CMH1 and CMH2 options.

specifies the level of confidence limits. The value of must be between 0 and 1, and the default is 0.05. A confidence level of produces % confidence limits. The default of ALPHA=0.05 produces 95% confidence limits.

ALPHA= applies to confidence limits requested by TABLES statement options. There is a separate ALPHA= option in the EXACT statement that sets the level of confidence limits for Monte Carlo estimates of exact p-values, which are requested in the EXACT statement.

requests Tarone’s adjustment in the Breslow-Day test for homogeneity of odds ratios. (You must specify the CMH option to compute the Breslow-Day test.) See the section Breslow-Day Test for Homogeneity of the Odds Ratios for more information.

requests the binomial proportion for one-way tables. When you specify the BINOMIAL option, by default PROC FREQ also provides the asymptotic standard error, asymptotic (Wald) and exact (Clopper-Pearson) confidence limits, and the asymptotic equality test for the binomial proportion.

You can specify binomial-options inside parentheses following the BINOMIAL option. The LEVEL= binomial-option identifies the variable level for which to compute the proportion. If you do not specify LEVEL=, PROC FREQ computes the proportion for the first level that appears in the output. The P= binomial-option specifies the null proportion for the binomial tests. If you do not specify P=, PROC FREQ uses P=0.5 by default.

You can also specify binomial-options to request additional tests and confidence limits for the binomial proportion. The EQUIV, NONINF, and SUP binomial-options request tests of equivalence, noninferiority, and superiority, respectively. Table 36.10 summarizes the binomial-options.

Available confidence limits for the binomial proportion include Agresti-Coull, exact (Clopper-Pearson), Jeffreys, Wald, and Wilson (score) confidence limits. You can specify more than one type of binomial confidence limits in the same analysis. If you do not specify any confidence limit requests with binomial-options, PROC FREQ computes Wald asymptotic confidence limits and exact (Clopper-Pearson) confidence limits by default. The ALPHA= option determines the confidence level, and the default of ALPHA=0.05 produces 95% confidence limits for the binomial proportion.

As part of the noninferiority, superiority, and equivalence analyses, PROC FREQ provides test-based confidence limits that have a confidence coefficient of % (Schuirmann 1999). The ALPHA= option determines the confidence level, and the default of ALPHA=0.05 produces 90% confidence limits. See the sections Noninferiority Test and Equivalence Test for details.

To request exact tests for the binomial proportion, specify the BINOMIAL option in the EXACT statement. PROC FREQ then computes exact p-values for all binomial tests that you request with binomial-options, which can include tests of noninferiority, superiority, and equivalence, in addition to the test of equality.

See the section Binomial Proportion for details.

You can specify the following binomial-options inside parentheses following the BINOMIAL option:

requests the BINOMIAL statistics for one-way tables and includes a continuity correction in the Wald confidence limits and tests. Specifying BINOMIALC is equivalent to specifying the BINOMIAL(CORRECT) option.

The BINOMIAL statistics include the binomial proportion, its asymptotic standard error, Wald and exact (Clopper-Pearson) confidence limits, and the asymptotic equality test for the binomial proportion by default. You can request exact binomial tests by specifying the BINOMIAL option in the EXACT statement.

You can specify binomial-options inside parentheses following BINOMIALC to request additional tests and confidence limits for the binomial proportion. The binomial-options are the same as those available with the BINOMIAL option (Table 36.10). See the description of the BINOMIAL option and the section Binomial Proportion for details.

displays each crosstabulation table cell’s contribution to the total Pearson chi-square statistic. The cell contribution is computed as

where frequency is the table cell frequency or count and expected is the expected cell frequency, which is computed under the null hypothesis that the row and column variables are independent. See the section Pearson Chi-Square Test for Two-Way Tables for details.

The CELLCHI2 option has no effect for one-way tables or for tables that are displayed with the LIST option.

requests chi-square tests of homogeneity or independence and measures of association based on the chi-square statistic. The tests include the Pearson chi-square, likelihood-ratio chi-square, and Mantel-Haenszel chi-square. The measures include the phi coefficient, the contingency coefficient, and Cramer’s . For tables, the CHISQ option also provides Fisher’s exact test and the continuity-adjusted chi-square. See the section Chi-Square Tests and Statistics for details.

For one-way tables, the CHISQ option provides a chi-square goodness-of-fit test for equal proportions. If you specify the null hypothesis proportions with the TESTP= option, PROC FREQ computes a chi-square goodness-of-fit test for the specified proportions. If you specify null hypothesis frequencies with the TESTF= option, PROC FREQ computes a chi-square goodness-of-fit test for the specified frequencies. See the section Chi-Square Test for One-Way Tables for more information.

To request Fisher’s exact test for tables larger than , use the FISHER option in the EXACT statement. Exact tests are also available for other CHISQ statistics, including the Pearson, likelihood-ratio, and Mantel-Haenszel chi-square, and the chi-square goodness-of-fit test for one-way tables. You can use the EXACT statement to request these tests. See the section Exact Statistics for details.

You can specify the following option in parentheses following the CHISQ option:

requests confidence limits for the MEASURES statistics. If you omit the MEASURES option, the CL option invokes MEASURES. You can set the level of the confidence limits by using the ALPHA= option. The default of ALPHA=0.5 produces 95% confidence limits. See the sections Measures of Association and Confidence Limits for more information.

requests Cochran-Mantel-Haenszel statistics, which test for association between the row and column variables after adjusting for the remaining variables in a multiway table. The Cochran-Mantel-Haenszel statistics include the nonzero correlation statistic, the row mean scores (ANOVA) statistic, and the general association statistic. In addition, for tables, the CMH option provides the adjusted Mantel-Haenszel and logit estimates of the odds ratio and relative risks, together with their confidence limits. For stratified tables, the CMH option provides the Breslow-Day test for homogeneity of odds ratios. (To request Tarone’s adjustment for the Breslow-Day test, specify the BDT cmh-option.) See the section Cochran-Mantel-Haenszel Statistics for details.

You can use the CMH1 or CMH2 option to control the number of CMH statistics that PROC FREQ computes.

For stratified tables, you can request Zelen’s exact test for equal odds ratios by specifying the EQOR option in the EXACT statement. See the section Zelen’s Exact Test for Equal Odds Ratios for details. You can request exact confidence limits for the common odds ratio by specifying the COMOR option in the EXACT statement. This option also provides a common odds ratio test. See the section Exact Confidence Limits for the Common Odds Ratio for details.

You can specify the following cmh-options in parentheses following the CMH option. These cmh-options, which apply to stratified tables, are also available with the CMH1 or CMH2 option.

requests the Cochran-Mantel-Haenszel correlation statistic. This option does not provide the CMH row mean scores (ANOVA) statistic or the general association statistic, which are provided by the CMH option. For tables larger than , the CMH1 option requires less memory than the CMH option, which can require an enormous amount of memory for large tables.

For tables, the CMH1 option also provides the adjusted Mantel-Haenszel and logit estimates of the odds ratio and relative risks, together with their confidence limits. For stratified tables, the CMH1 option provides the Breslow-Day test for homogeneity of odds ratios.

The cmh-options available with the CMH1 option are the same as those available with the CMH option. See the description of the CMH option for details.

requests the Cochran-Mantel-Haenszel correlation statistic and the row mean scores (ANOVA) statistic. This option does not provide the CMH general association statistic, which is provided by the CMH option. For tables larger than , the CMH2 option requires less memory than the CMH option, which can require an enormous amount of memory for large tables.

For tables, the CMH1 option also provides the adjusted Mantel-Haenszel and logit estimates of the odds ratio and relative risks, together with their confidence limits. For stratified tables, the CMH1 option provides the Breslow-Day test for homogeneity of odds ratios.

The cmh-options available with the CMH2 option are the same as those available with the CMH option. See the description of the CMH option for details.

specifies the label to use for crosstabulation tables in the contents file, the Results window, and the trace record. For information about output presentation, see the SAS Output Delivery System: User's Guide.

If you omit the CONTENTS= option, the contents label for crosstabulation tables is "Cross-Tabular Freq Table" by default.

Note that contents labels for all crosstabulation tables that are produced by a single TABLES statement use the same text. To specify different contents labels for different crosstabulation tables, request the tables in separate TABLES statements and use the CONTENTS= option in each TABLES statement.

To remove the crosstabulation table entry from the contents file, you can specify a null label with CONTENTS=''.

The CONTENTS= option affects only contents labels for crosstabulation tables. It does not affect contents labels for other PROC FREQ tables.

To specify the contents label for any PROC FREQ table, you can use PROC TEMPLATE to create a customized table definition. The CONTENTS_LABEL attribute in the DEFINE TABLE statement of PROC TEMPLATE specifies the contents label for the table. See the chapter "The TEMPLATE Procedure" in the SAS Output Delivery System: User's Guide for more information.

specifies the convergence criterion for computing the polychoric correlation, which you request with the PLCORR option. The CONVERGE= value must be a positive number. By default CONVERGE=0.0001. Iterative computation of the polychoric correlation stops when the convergence measure falls below the value of CONVERGE= or when the number of iterations exceeds the value specified in the MAXITER= option, whichever happens first. See the section Polychoric Correlation for details.

displays crosstabulation tables in ODS column format instead of the default crosstabulation cell format. In a CROSSLIST table display, the rows correspond to the crosstabulation table cells, and the columns correspond to descriptive statistics such as Frequency and Percent. The CROSSLIST table displays the same information as the default crosstabulation table, but uses an ODS column format instead of the table cell format. See the section Multiway Tables for details about the contents of the CROSSLIST table.

You can control the contents of a CROSSLIST table with the same options available for the default crosstabulation table. These include the NOFREQ, NOPERCENT, NOROW, and NOCOL options. You can request additional information in a CROSSLIST table with the CELLCHI2, DEVIATION, EXPECTED, MISSPRINT, and TOTPCT options.

The FORMAT= option and the CUMCOL option have no effect for CROSSLIST tables. You cannot specify both the LIST option and the CROSSLIST option in the same TABLES statement.

You can use the NOSPARSE option to suppress display of variable levels with zero frequency in CROSSLIST tables. By default for CROSSLIST tables, PROC FREQ displays all levels of the column variable within each level of the row variable, including any column variable levels with zero frequency for that row. And for multiway tables displayed with the CROSSLIST option, the procedure displays all levels of the row variable for each stratum of the table by default, including any row variable levels with zero frequency for the stratum.

displays the cumulative column percentages in the cells of the crosstabulation table. The CUMCOL option does not apply to crosstabulation tables produced with the LIST or CROSSLIST option.

displays the deviation of the frequency from the expected frequency for each cell of the crosstabulation table. See the section Pearson Chi-Square Test for Two-Way Tables for details. The DEVIATION option does not apply to crosstabulation tables produced with the LIST option.

displays the expected cell frequencies under the hypothesis of independence (or homogeneity) for crosstabulation tables. See the section Pearson Chi-Square Test for Two-Way Tables for details. The EXPECTED option does not apply to tables produced with the LIST option.

requests Fisher’s exact test for tables that are larger than . (For tables, the CHISQ option provides Fisher’s exact test.) This test is also known as the Freeman-Halton test. See the sections Fisher’s Exact Test and Exact Statistics for more information.

If you omit the CHISQ option in the TABLES statement, the FISHER option invokes CHISQ. You can also request Fisher’s exact test by specifying the FISHER option in the EXACT statement.

Note: PROC FREQ computes exact tests with fast and efficient algorithms that are superior to direct enumeration. Exact tests are appropriate when a data set is small, sparse, skewed, or heavily tied. For some large problems, computation of exact tests might require a considerable amount of time and memory. Consider using asymptotic tests for such problems. Alternatively, when asymptotic methods might not be sufficient for such large problems, consider using Monte Carlo estimation of exact p-values. See the section Computational Resources for more information.

specifies a format for the following crosstabulation table cell values: frequency, expected frequency, and deviation. PROC FREQ also uses the specified format to display the row and column total frequencies and the overall total frequency in crosstabulation tables.

You can specify any standard SAS numeric format or a numeric format defined with the FORMAT procedure. The format length must not exceed 24. If you omit the FORMAT= option, by default PROC FREQ uses the BEST6. format to display frequencies less than 1E6, and the BEST7. format otherwise.

The FORMAT= option applies only to crosstabulation tables displayed in the default format. It does not apply to crosstabulation tables produced with the LIST or CROSSLIST option.

To change display formats in any FREQ table, you can use PROC TEMPLATE. See the chapter "The TEMPLATE Procedure" in the SAS Output Delivery System: User's Guide for more information.

requests the Gail-Simon test for qualitative interaction, which applies to stratified tables. See the section Gail-Simon Test for Qualitative Interactions for details.

The COLUMN= option specifies the column of the risk differences to use in computing the Gail-Simon test. By default, PROC FREQ uses column 1 risk differences. If you specify COLUMN=2, PROC FREQ uses column 2 risk differences.

requests the Jonckheere-Terpstra test. See the section Jonckheere-Terpstra Test for details.

displays two-way to -way crosstabulation tables in a list format instead of the default crosstabulation cell format. The LIST option displays the entire multiway table in one table, instead of displaying a separate two-way table for each stratum. See the section Multiway Tables for details.

The LIST option is not available when you also specify statistical options. You must use the standard crosstabulation table display or the CROSSLIST display when you request statistical tests or measures.

specifies the maximum number of iterations for computing the polychoric correlation, which you request with the PLCORR option. The value of the MAXITER= option must be a positive integer. By default MAXITER=20. Iterative computation of the polychoric correlation stops when the number of iterations exceeds the MAXITER= value or when the convergence measures falls below the value of the CONVERGE= option, whichever happens first. See the section Polychoric Correlation for details.

requests several measures of association and their asymptotic standard errors. The MEASURES option provides the following statistics: gamma, Kendall’s tau-, Stuart’s tau-, Somers’ , Somers’ , the Pearson and Spearman correlation coefficients, lambda (symmetric and asymmetric), and uncertainty coefficients (symmetric and asymmetric). To request confidence limits for these measures of association, you can specify the CL option.

For tables, the MEASURES option also provides the odds ratio, column 1 relative risk, column 2 relative risk, and the corresponding confidence limits. Alternatively, you can obtain the odds ratio and relative risks, without the other measures of association, by specifying the RELRISK option.

See the section Measures of Association for details.

You can use the TEST statement to request asymptotic tests for the following measures of association: gamma, Kendall’s tau-, Stuart’s tau-, Somers’ , Somers’ , and the Pearson and Spearman correlation coefficients. You can use the EXACT statement to request exact confidence limits for the odds ratio, exact unconditional confidence limits for the relative risks, and exact tests for the following measures of association: Kendall’s tau-, Stuart’s tau-, Somers’ and , and the Pearson and Spearman correlation coefficients. See the section Exact Statistics for more information.

treats missing values as a valid nonmissing level for all TABLES variables. The MISSING option displays the missing levels in frequency and crosstabulation tables and includes them in all calculations of percentages, tests, and measures.

By default, if you do not specify the MISSING or MISSPRINT option, an observation is excluded from a table if it has a missing value for any of the variables in the TABLES request. When PROC FREQ excludes observations with missing values, it displays the total frequency of missing observations below the table. See the section Missing Values for more information.

displays missing value frequencies in frequency and crosstabulation tables but does not include the missing value frequencies in any computations of percentages, tests, or measures.

By default, if you do not specify the MISSING or MISSPRINT option, an observation is excluded from a table if it has a missing value for any of the variables in the TABLES request. When PROC FREQ excludes observations with missing values, it displays the total frequency of missing observations below the table. See the section Missing Values for more information.

suppresses the display of column percentages in crosstabulation table cells.

suppresses the display of cumulative frequencies and percentages in one-way frequency tables. The NOCUM option also suppresses the display of cumulative frequencies and percentages in crosstabulation tables in list format, which you request with the LIST option.

suppresses the display of cell frequencies in crosstabulation tables. The NOFREQ option also suppresses row total frequencies. This option has no effect for one-way tables or for crosstabulation tables in list format, which you request with the LIST option.

suppresses the display of overall percentages in crosstabulation tables. These percentages include the cell percentages of the total (two-way) table frequency, as well as the row and column percentages of the total table frequency. To suppress the display of cell percentages of row or column totals, use the NOROW or NOCOL option, respectively.

For one-way frequency tables and crosstabulation tables in list format, the NOPERCENT option suppresses the display of percentages and cumulative percentages.

suppresses the display of frequency and crosstabulation tables but displays all requested tests and statistics. To suppress the display of all output, including tests and statistics, use the NOPRINT option in the PROC FREQ statement.

suppresses the display of row percentages in crosstabulation table cells.

suppresses the display of cells with a zero frequency count in LIST output and omits them from the OUT= data set. The NOSPARSE option applies when you specify the ZEROS option in the WEIGHT statement to include observations with zero weights. By default, the ZEROS option invokes the SPARSE option, which displays table cells with a zero frequency count in the LIST output and includes them in the OUT= data set. See the description of the ZEROS option for more information.

The NOSPARSE option also suppresses the display of variable levels with zero frequency in CROSSLIST tables. By default for CROSSLIST tables, PROC FREQ displays all levels of the column variable within each level of the row variable, including any column variable levels with zero frequency for that row. For multiway tables displayed with the CROSSLIST option, the procedure displays all levels of the row variable for each stratum of the table by default, including any row variable levels with zero frequency for the stratum.

suppresses the log warning message about the validity of the asymptotic Pearson chi-square test. By default, PROC FREQ provides a warning about the validity of the asymptotic Pearson chi-square test when more than 20cells have expected frequencies that are less than 5. This warning message appears in the log if you specify the NOPRINT option in the PROC FREQ statement,

The NOWARN option is equivalent to the CHISQ(WARN=NOLOG) option. You can also use the CHISQ(WARN=) option to suppress the warning message in the display and to request a warning variable in the chi-square ODS output data set or in the OUTPUT data set.

names an output data set that contains frequency or crosstabulation table counts and percentages. If more than one table request appears in the TABLES statement, the contents of the OUT= data set correspond to the last table request in the TABLES statement. The OUT= data set variable COUNT contains the frequencies and the variable PERCENT contains the percentages. See the section Output Data Sets for details. You can specify the following options to include additional information in the OUT= data set: OUTCUM, OUTEXPECT, and OUTPCT.

includes cumulative frequencies and cumulative percentages in the OUT= data set for one-way tables. The variable CUM_FREQ contains the cumulative frequencies, and the variable CUM_PCT contains the cumulative percentages. See the section Output Data Sets for details. The OUTCUM option has no effect for two-way or multiway tables.

includes expected cell frequencies in the OUT= data set for crosstabulation tables. The variable EXPECTED contains the expected cell frequencies. See the section Output Data Sets for details. The EXPECTED option has no effect for one-way tables.

includes the following additional variables in the OUT= data set for crosstabulation tables:

PCT_COL

percentage of column frequency

PCT_ROW

percentage of row frequency

PCT_TABL

percentage of stratum (two-way table) frequency, for -way tables where

See the section Output Data Sets for details. The OUTPCT option has no effect for one-way tables.

requests the polychoric correlation coefficient. For tables, this statistic is more commonly known as the tetrachoric correlation coefficient, and it is labeled as such in the displayed output. See the section Polychoric Correlation for details. Also see the descriptions of the CONVERGE= and MAXITER= options, which you can specify to control the iterative computation of the polychoric correlation coefficient.

If you omit the MEASURES option, the PLCORR option invokes MEASURES.

controls the plots that are produced through ODS Graphics. Plot-requests identify the plots, and plot-options control the appearance and content of the plots. You can specify plot-options in parentheses following a plot-request. A global-plot-option applies to all plots for which it is available, unless it is altered by a specific plot-option. You can specify global-plot-options in parentheses following the PLOTS option.

When you specify only one plot-request, you can omit the parentheses around the request. For example:

 plots=all
 plots=freqplot
 plots=(freqplot oddsratioplot)
 plots(only)=(cumfreqplot deviationplot)

ODS Graphics must be enabled before requesting plots. For example:

ods graphics on;
proc freq;
   tables treatment*response / chisq plots=freqplot;
   weight wt;
run;
ods graphics off;

For more information about enabling and disabling ODS Graphics, see the section Enabling and Disabling ODS Graphics in Chapter 21, Statistical Graphics Using ODS.

If ODS Graphics is enabled but you do not specify the PLOTS= option, PROC FREQ produces all plots that are associated with the analyses that you request with the exception of the frequency and cumulative frequency plots. To produce a frequency plot or cumulative frequency plot when ODS Graphics is enabled, you must specify the FREQPLOT or CUMFREQPLOT plot-request, respectively, in the PLOTS= option. PROC FREQ produces the remaining plots (listed in Table 36.11) by default when you request the corresponding TABLES statement options. You can suppress default plots and request specific plots by using the PLOTS(ONLY)= option; PLOTS(ONLY)=(plot-requests) produces only the plots that are specified as plot-requests. You can suppress all plots with the PLOTS=NONE option. The PLOTS= option has no effect when you specify the NOPRINT option in the PROC FREQ statement.

Table 36.11 lists the available plot-requests, together with their plot-options and required TABLES statement options.

Also requires EXACT statment

Global Plot Options

A global-plot-option applies to all plots for which the option is available, unless it is altered by a specific plot-option. You can specify global-plot-options in parentheses following the PLOTS option.

The following specific plot-options are available as global-plot-options: CLDISPLAY=, COLUMN=, EXACT, LOGBASE=, NPANELPOS=, ORDER=, ORIENT=, RANGE=, SCALE=, STATS, and TYPE=.

These plot-options are described in the section "Plot Options." Additionally, you can specify the following global-plot-option in parentheses following the PLOTS option:

Plot Requests

The following plot-requests are available with the PLOTS= option:

Plot Options

You can specify the following plot-options in parentheses after a plot-request:

displays the weights that PROC FREQ uses to compute the weighted kappa coefficient. You must also specify the AGREE option to request the weighted kappa coefficient. You can specify (WT=FC) with the AGREE option to request Fleiss-Cohen weights. By default, PROC FREQ uses Cicchetti-Allison weights to compute the weighted kappa coefficient. See the section Weighted Kappa Coefficient for details.

requests relative risk measures and their confidence limits for tables. These measures include the odds ratio and the column 1 and 2 relative risks. See the section Odds Ratio and Relative Risks for 2 x 2 Tables for details.

You can also obtain the RELRISK measures by specifying the MEASURES option, which produces other measures of association in addition to the relative risks.

You can request exact confidence limits for the odds ratio by specifying the OR option in the EXACT statement. You can request exact unconditional confidence limits for the relative risks by specifying the RELRISK option in the EXACT statement. See the sections Exact Confidence Limits for the Odds Ratio and Exact Unconditional Confidence Limits for the Relative Risk for more information.

requests risks (binomial proportions) and risk differences for tables. When you specify the RISKDIFF option, PROC FREQ provides the row 1 risk, row 2 risk, total (overall) risk, and risk difference (row 1 – row 2), together with their asymptotic standard errors and Wald confidence limits. PROC FREQ also provides exact (Clopper-Pearson) confidence limits for the row 1, row 2, and total risks by default. You can request exact unconditional confidence limits for the risk difference by specifying the RISKDIFF option in the EXACT statement. See the section Risks and Risk Differences for details. PROC FREQ displays these results in the column 1 and column 2 "Risk Estimates" tables.

You can specify riskdiff-options inside parentheses following the RISKDIFF option to request tests and additional confidence limits for the risk difference. Table 36.12 summarizes the riskdiff-options.

The EQUIV, NONINF, and SUP riskdiff-options request tests of equivalence, noninferiority, and superiority, respectively, for the risk difference. Available test methods include Farrington-Manning, Hauck-Anderson, and Newcombe score, in addition to the Wald test.

As part of the noninferiority, superiority, and equivalence analyses, PROC FREQ provides test-based confidence limits that have a confidence coefficient of % (Schuirmann 1999). The ALPHA= option determines the confidence level, and the default of ALPHA=0.05 produces 90% confidence limits. See the sections Noninferiority Tests and Equivalence Tests for details.

The CL= riskdiff-option requests confidence limits for the risk difference. Available confidence limit types include exact unconditional, Farrington-Manning, Hauck-Anderson, Newcombe score, and Wald. You can request more than one type of confidence limits in the same analysis. If you specify the CORRECT riskdiff-option, PROC FREQ includes continuity corrections in the Newcombe and Wald confidence limits. PROC FREQ displays the confidence limits in the "Proportion (Risk) Difference Confidence Limits" table.

The ALPHA= option determines the level of the confidence limits that the CL= riskdiff-option provides. The default of ALPHA=0.05 produces 95% confidence limits for the risk difference.

The CL=EXACT riskdiff-option displays exact unconditional confidence limits in the "Proportion (Risk) Difference Confidence Limits" table. When you use CL=EXACT, you must also request computation of the exact confidence limits by specifying the RISKDIFF option in the EXACT statement.

You can specify the following riskdiff-options inside parentheses following the RISKDIFF option:

requests the RISKDIFF statistics for tables and includes continuity corrections in the Wald confidence limits, Wald tests, and Newcombe confidence limits. Specifying RISKDIFFC is equivalent to specifying the RISKDIFF(CORRECT) option.

The RISKDIFF statistics include risks (binomial proportions) and risk differences for tables. PROC FREQ provides the row 1 risk, row 2 risk, total risk, and risk difference (row 1 – row 2), together with their asymptotic standard errors and Wald confidence limits. PROC FREQ also provides exact (Clopper-Pearson) confidence limits for the row 1, row 2, and total risks by default. You can request exact unconditional confidence limits for the risk difference by specifying the RISKDIFF option in the EXACT statement.

You can specify riskdiff-options inside parentheses following RISKDIFFC to request tests and additional confidence limits for the risk difference. The riskdiff-options are the same as those available with the RISKDIFF option (Table 36.12). See the description of the RISKDIFF option and the section Risks and Risk Differences for details.

specifies the type of row and column scores that PROC FREQ uses to compute the following statistics: Mantel-Haenszel chi-square, Pearson correlation, Cochran-Armitage test for trend, weighted kappa coefficient, and Cochran-Mantel-Haenszel statistics. The value of type can be one of the following:

• MODRIDIT

• RANK

• RIDIT

• TABLE

See the section Scores for descriptions of these score types.

If you do not specify the SCORES= option, PROC FREQ uses SCORES=TABLE by default. For character variables, the row and column TABLE scores are the row and column numbers. That is, the TABLE score is 1 for row 1, 2 for row 2, and so on. For numeric variables, the row and column TABLE scores equal the variable values. See the section Scores for details. Using MODRIDIT, RANK, or RIDIT scores yields nonparametric analyses.

You can use the SCOROUT option to display the row and column scores.

displays the row and column scores that PROC FREQ uses to compute score-based tests and statistics. You can specify the score type with the SCORES= option. See the section Scores for details.

The scores are computed and displayed only when PROC FREQ computes statistics for two-way tables. You can use ODS to store the scores in an output data set. See the section ODS Table Names for more information.

reports all possible combinations of the variable values for an n-way table when , even if a combination does not occur in the data. The SPARSE option applies only to crosstabulation tables displayed in LIST format and to the OUT= output data set. If you do not use the LIST or OUT= option, the SPARSE option has no effect.

When you specify the SPARSE and LIST options, PROC FREQ displays all combinations of variable values in the table listing, including those with a frequency count of zero. By default, without the SPARSE option, PROC FREQ does not display zero-frequency levels in LIST output. When you use the SPARSE and OUT= options, PROC FREQ includes empty crosstabulation table cells in the output data set. By default, PROC FREQ does not include zero-frequency table cells in the output data set.

See the section Missing Values for more information.

specifies the null hypothesis frequencies for a one-way chi-square goodness-of-fit test, which you request with the CHISQ option. See the section Chi-Square Test for One-Way Tables for details.

You can separate the TESTF= values with blanks or commas. The number of values must equal the number of variable levels in the one-way table. The sum of the values must equal the total frequency for the one-way table. List the values in the order in which the corresponding variable levels appear in the output. If you omit the CHISQ option, the TESTF= option invokes CHISQ.

specifies the null hypothesis proportions for a one-way chi-square goodness-of-fit test, which you request with the CHISQ option. See the section Chi-Square Test for One-Way Tables for details.

You can separate the TESTP= values with blanks or commas. The number of values must equal the number of variable levels in the one-way table. List the values in the order in which the corresponding variable levels appear in the output. You can specify values in probability form as numbers between 0 and 1, where the proportions sum to 1. Or you can specify values in percentage form as numbers between 0 and 100, where the percentages sum to 100. If you omit the CHISQ option, the TESTP= option invokes CHISQ.

displays the percentage of the total multiway table frequency in crosstabulation tables for -way tables, where . By default, PROC FREQ displays the percentage of the individual two-way table frequency but does not display the percentage of the total frequency for multiway crosstabulation tables. See the section Multiway Tables for more information.

The percentage of total multiway table frequency is displayed by default when you specify the LIST option. It is also provided by default in the PERCENT variable in the OUT= output data set.

requests the Cochran-Armitage test for trend. The table must be or to compute the trend test. See the section Cochran-Armitage Test for Trend for details.