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<table width="100%" summary="page for summary.pmatrix.class"><tr><td>summary.pmatrix.class</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>
Summarize pmatrix.class objects
</h2>

<h3>Description</h3>

<p>S3 Method for <code>summary</code> of objects of class pmatrix.class.
Summarize checks of nonintersection using method pmatrix.
</p>


<h3>Usage</h3>

<pre>
## S3 method for class 'pmatrix.class'
summary(object, ...)
</pre>


<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>object</code></td>
<td>
<p>list produced by <code>check.pmatrix</code></p>
</td></tr>
<tr valign="top"><td><code>...</code></td>
<td>
<p>Optional parameters will be ignored</p>
</td></tr>  
</table>


<h3>Details</h3>

<p>For obtaining the P++ and P&ndash; matrix, see examples.
</p>


<h3>Value</h3>

<p>Matrix with <code>ncol(X)</code> rows and 10 columns, 
showing for each item a summary of the violations of nonintersection using method pmatrix: 
<code>itemH</code> = Item-scalability coefficient; 
<code>#ac</code> = number of active pairs that were investigated; 
<code>#vi</code> = number of violations in which the item is involved;
<code>#vi/#ac</code> = propotion of active pairs that is involved in a violation;
<code>maxvi</code> = maximum violation;
<code>sum</code> = sum of all violations;
<code>zmax</code>  = maximum z-value;
<code>zsig</code> = number of significant z-values;
<code>crit</code> = Crit value (Molenaar &amp; Sijtsma, 2000, pp. 49, 74). 
</p>


<h3>Author(s)</h3>

<p>L. A. van der Ark <a href="mailto:L.A.vanderArk@uva.nl">L.A.vanderArk@uva.nl</a>
</p>


<h3>References</h3>

<p>Mokken, R. J. (1971) 
<em>A Theory and Procedure of Scale Analysis</em>. 
De Gruyter.
</p>
<p>Molenaar, I.W., &amp; Sijtsma, K. (2000) 
<em>User's Manual MSP5 for Windows</em> [Software manual].
IEC ProGAMMA.
</p>
<p>Sijtsma, K., &amp; Molenaar, I. W. (2002)
<em>Introduction to nonparametric item response theory</em>.
Sage.
</p>
<p>Van der Ark, L. A. (2007). 
Mokken scale analysis in <span class="pkg">R</span>. 
<em>Journal of Statistical Software</em>.
\Sexpr[results=rd,stage=build]{tools:::Rd_expr_doi("10.18637/jss.v020.i11")}
</p>


<h3>See Also</h3>

<p><code>check.pmatrix</code>, <code>plot.pmatrix.class</code>
</p>


<h3>Examples</h3>

<pre>
data(acl)
Communality &lt;- acl[,1:10]
pmatrix.list &lt;- check.pmatrix(Communality)
plot(pmatrix.list)
summary(pmatrix.list)

# Small example showing how to retrieve the P++ matrix and the P-- matrix
SmallExample &lt;- acl[,1:4]
pmatrix.list &lt;- check.pmatrix(SmallExample)
pmatrix.list$results$Ppp
pmatrix.list$results$Pmm
</pre>


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