|
|||||||||||||||||||
| 30 day Evaluation Version distributed via the Maven Jar Repository. Clover is not free. You have 30 days to evaluate it. Please visit http://www.thecortex.net/clover to obtain a licensed version of Clover | |||||||||||||||||||
| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| MetaAnalysis.java | 38.9% | 40.3% | 38.5% | 39.7% |
|
||||||||||||||
| 1 |
package baseCode.math.metaanalysis;
|
|
| 2 |
|
|
| 3 |
import baseCode.math.Constants;
|
|
| 4 |
import cern.colt.list.DoubleArrayList;
|
|
| 5 |
import cern.jet.stat.Descriptive;
|
|
| 6 |
import cern.jet.stat.Probability;
|
|
| 7 |
|
|
| 8 |
/**
|
|
| 9 |
* Statistics for meta-analysis. Methods from Cooper and Hedges (CH); Hunter and Schmidt (HS).
|
|
| 10 |
* <p>
|
|
| 11 |
* In this class "conditional variance" means the variance for one data set. Unconditional means "between data set", or
|
|
| 12 |
* across data set.
|
|
| 13 |
* <p>
|
|
| 14 |
* Copyright (c) 2004
|
|
| 15 |
* </p>
|
|
| 16 |
* <p>
|
|
| 17 |
* Institution: Columbia University
|
|
| 18 |
* </p>
|
|
| 19 |
*
|
|
| 20 |
* @author Paul Pavlidis
|
|
| 21 |
* @version $Id: MetaAnalysis.java,v 1.5 2005/03/21 18:01:03 pavlidis Exp $
|
|
| 22 |
*/
|
|
| 23 |
|
|
| 24 |
public abstract class MetaAnalysis { |
|
| 25 |
|
|
| 26 |
/**
|
|
| 27 |
* Fisher's method for combining p values. (Cooper and Hedges 15-8)
|
|
| 28 |
*
|
|
| 29 |
* @param pvals DoubleArrayList
|
|
| 30 |
* @return double
|
|
| 31 |
*/
|
|
| 32 | 0 |
protected double fisherCombinePvalues( DoubleArrayList pvals ) { |
| 33 | 0 |
double r = 0.0;
|
| 34 | 0 |
for ( int i = 0, n = pvals.size(); i < n; i++ ) { |
| 35 | 0 |
r += Math.log( pvals.getQuick( i ) ); |
| 36 |
} |
|
| 37 | 0 |
r *= -2.0; |
| 38 | 0 |
return Probability.chiSquare( r, 2.0 * pvals.size() );
|
| 39 |
} |
|
| 40 |
|
|
| 41 |
/**
|
|
| 42 |
* Fisher's method for combining p values (Cooper and Hedges 15-8)
|
|
| 43 |
* <p>
|
|
| 44 |
* Use for p values that have already been log transformed.
|
|
| 45 |
*
|
|
| 46 |
* @param pvals DoubleArrayList
|
|
| 47 |
* @return double
|
|
| 48 |
*/
|
|
| 49 | 0 |
protected double fisherCombineLogPvalues( DoubleArrayList pvals ) { |
| 50 | 0 |
double r = 0.0;
|
| 51 | 0 |
for ( int i = 0, n = pvals.size(); i < n; i++ ) { |
| 52 | 0 |
r += pvals.getQuick( i ); |
| 53 |
} |
|
| 54 | 0 |
r *= -2.0; |
| 55 | 0 |
return Probability.chiSquare( r, 2.0 * pvals.size() );
|
| 56 |
} |
|
| 57 |
|
|
| 58 |
/**
|
|
| 59 |
* The "Q" statistic used to test homogeneity of effect sizes. (Cooper and Hedges 18-6)
|
|
| 60 |
*
|
|
| 61 |
* @param effectSizes DoubleArrayList
|
|
| 62 |
* @param variances DoubleArrayList
|
|
| 63 |
* @param globalMean double
|
|
| 64 |
* @return double
|
|
| 65 |
*/
|
|
| 66 | 24 |
protected double qStatistic( DoubleArrayList effectSizes, DoubleArrayList variances, double globalMean ) { |
| 67 |
|
|
| 68 | 0 |
if ( !( effectSizes.size() == variances.size() ) ) throw new IllegalArgumentException( "Unequal sizes" ); |
| 69 |
|
|
| 70 | 24 |
double r = 0.0;
|
| 71 | 24 |
for ( int i = 0, n = effectSizes.size(); i < n; i++ ) { |
| 72 | 468 |
r += Math.pow( effectSizes.getQuick( i ) - globalMean, 2.0 ) / variances.getQuick( i ); |
| 73 |
} |
|
| 74 | 24 |
return r;
|
| 75 |
} |
|
| 76 |
|
|
| 77 |
/**
|
|
| 78 |
* Test for statistical significance of Q.
|
|
| 79 |
*
|
|
| 80 |
* @param Q - computed using qStatistic
|
|
| 81 |
* @param N - number of studies.
|
|
| 82 |
* @see qStatistic
|
|
| 83 |
* @return The upper tail chi-square probability for Q with N - degrees of freedom.
|
|
| 84 |
*/
|
|
| 85 | 0 |
public double qTest( double Q, double N ) { |
| 86 | 0 |
return Probability.chiSquareComplemented( N - 1, Q );
|
| 87 |
} |
|
| 88 |
|
|
| 89 |
/**
|
|
| 90 |
* General formula for weighted mean of effect sizes. Cooper and Hedges 18-1, or HS pg. 100.
|
|
| 91 |
* <p>
|
|
| 92 |
* In HS, the weights are simply the sample sizes. For CH, the weights are 1/v for a fixed effect model. Under a
|
|
| 93 |
* random effects model, we would use 1/(v + v_bs) where v_bs is the between-studies variance.
|
|
| 94 |
*
|
|
| 95 |
* @param effectSizes
|
|
| 96 |
* @param sampleSizes
|
|
| 97 |
* @return
|
|
| 98 |
*/
|
|
| 99 | 41 |
protected double weightedMean( DoubleArrayList effectSizes, DoubleArrayList weights ) { |
| 100 |
|
|
| 101 | 0 |
if ( !( effectSizes.size() == weights.size() ) ) throw new IllegalArgumentException( "Unequal sizes" ); |
| 102 |
|
|
| 103 | 41 |
double wm = 0.0;
|
| 104 | 41 |
for ( int i = 0; i < effectSizes.size(); i++ ) { |
| 105 | 800 |
wm += weights.getQuick( i ) * effectSizes.getQuick( i ); |
| 106 |
} |
|
| 107 |
|
|
| 108 | 41 |
double s = Descriptive.sum( weights );
|
| 109 |
|
|
| 110 | 0 |
if ( s == 0.0 ) return 0.0; |
| 111 | 41 |
return wm /= s;
|
| 112 |
} |
|
| 113 |
|
|
| 114 |
/**
|
|
| 115 |
* General formula for weighted mean of effect sizes including quality index scores for each value. Cooper and Hedges
|
|
| 116 |
* 18-1, or HS pg. 100.
|
|
| 117 |
*
|
|
| 118 |
* @param effectSizes
|
|
| 119 |
* @param sampleSizes
|
|
| 120 |
* @param qualityIndices
|
|
| 121 |
* @return
|
|
| 122 |
*/
|
|
| 123 | 0 |
protected double weightedMean( DoubleArrayList effectSizes, DoubleArrayList weights, DoubleArrayList qualityIndices ) { |
| 124 |
|
|
| 125 | 0 |
if ( !( effectSizes.size() == weights.size() && weights.size() == qualityIndices.size() ) )
|
| 126 | 0 |
throw new IllegalArgumentException( "Unequal sizes" ); |
| 127 |
|
|
| 128 | 0 |
double wm = 0.0;
|
| 129 | 0 |
for ( int i = 0; i < effectSizes.size(); i++ ) { |
| 130 | 0 |
wm += weights.getQuick( i ) * effectSizes.getQuick( i ) * qualityIndices.getQuick( i ); |
| 131 |
} |
|
| 132 | 0 |
return wm /= ( Descriptive.sum( weights ) * Descriptive.sum( qualityIndices ) );
|
| 133 |
} |
|
| 134 |
|
|
| 135 |
/**
|
|
| 136 |
* CH 18-3. Can be used for fixed or random effects model, the variances just have to computed differently.
|
|
| 137 |
*
|
|
| 138 |
* <pre>
|
|
| 139 |
* v_dot = 1/sum_i=1ˆk ( 1/v_i)
|
|
| 140 |
* </pre>
|
|
| 141 |
*
|
|
| 142 |
* @param variances
|
|
| 143 |
* @return
|
|
| 144 |
*/
|
|
| 145 | 17 |
protected double metaVariance( DoubleArrayList variances ) { |
| 146 | 17 |
double var = 0.0;
|
| 147 | 17 |
for ( int i = 0; i < variances.size(); i++ ) { |
| 148 | 332 |
var += 1.0 / variances.getQuick( i ); |
| 149 |
} |
|
| 150 | 17 |
if ( var == 0.0 ) {
|
| 151 | 0 |
var = Double.MIN_VALUE; |
| 152 |
// throw new IllegalStateException( "Variance of zero" );
|
|
| 153 |
} |
|
| 154 | 17 |
return 1.0 / var;
|
| 155 |
} |
|
| 156 |
|
|
| 157 |
/**
|
|
| 158 |
* CH 18-3 version 2 for quality weighted. ( page 266 ) in Fixed effects model.
|
|
| 159 |
*
|
|
| 160 |
* <pre>
|
|
| 161 |
*
|
|
| 162 |
*
|
|
| 163 |
*
|
|
| 164 |
*
|
|
| 165 |
*
|
|
| 166 |
*
|
|
| 167 |
*
|
|
| 168 |
* v_dot = [ sum_i=1ˆk ( q_i ˆ 2 * w_i) ]/[ sum_i=1ˆk q_i * w_i ]ˆ2
|
|
| 169 |
*
|
|
| 170 |
*
|
|
| 171 |
*
|
|
| 172 |
*
|
|
| 173 |
*
|
|
| 174 |
*
|
|
| 175 |
*
|
|
| 176 |
* </pre>
|
|
| 177 |
*
|
|
| 178 |
* @param variances
|
|
| 179 |
* @return
|
|
| 180 |
*/
|
|
| 181 | 0 |
protected double metaVariance( DoubleArrayList weights, DoubleArrayList qualityIndices ) { |
| 182 | 0 |
double num = 0.0;
|
| 183 | 0 |
double denom = 0.0;
|
| 184 | 0 |
for ( int i = 0; i < weights.size(); i++ ) { |
| 185 | 0 |
num += Math.pow( weights.getQuick( i ), 2 ) * qualityIndices.getQuick( i ); |
| 186 | 0 |
denom += Math.pow( weights.getQuick( i ) * qualityIndices.getQuick( i ), 2 ); |
| 187 |
} |
|
| 188 | 0 |
if ( denom == 0.0 ) {
|
| 189 | 0 |
throw new IllegalStateException( "Attempt to divide by zero." ); |
| 190 |
} |
|
| 191 | 0 |
return num / denom;
|
| 192 |
} |
|
| 193 |
|
|
| 194 |
/**
|
|
| 195 |
* Test statistic for H0: effectSize == 0. CH 18-5. For fixed effects model.
|
|
| 196 |
*
|
|
| 197 |
* @param metaEffectSize
|
|
| 198 |
* @param metaVariance
|
|
| 199 |
* @return
|
|
| 200 |
*/
|
|
| 201 | 0 |
protected double metaZscore( double metaEffectSize, double metaVariance ) { |
| 202 | 0 |
return Math.abs( metaEffectSize ) / Math.sqrt( metaVariance );
|
| 203 |
} |
|
| 204 |
|
|
| 205 |
/**
|
|
| 206 |
* CH sample variance under random effects model, equation 18-20
|
|
| 207 |
*
|
|
| 208 |
* @param
|
|
| 209 |
* @return
|
|
| 210 |
*/
|
|
| 211 | 0 |
protected double metaRESampleVariance( DoubleArrayList effectSizes ) { |
| 212 | 0 |
return Descriptive.sampleVariance( effectSizes, Descriptive.mean( effectSizes ) );
|
| 213 |
} |
|
| 214 |
|
|
| 215 |
/**
|
|
| 216 |
* CH estimate of between-studies variance, equation 18-22, for random effects model.
|
|
| 217 |
*
|
|
| 218 |
* @param effectSizes
|
|
| 219 |
* @param variances
|
|
| 220 |
* @return
|
|
| 221 |
*/
|
|
| 222 |
// protected double metaREVariance( DoubleArrayList effectSizes,
|
|
| 223 |
// DoubleArrayList variances ) {
|
|
| 224 |
// return Math.max( metaRESampleVariance( effectSizes )
|
|
| 225 |
// - Descriptive.mean( variances ), 0.0 );
|
|
| 226 |
// }
|
|
| 227 |
/**
|
|
| 228 |
* CH equation 18-23. Another estimator of the between-studies variance s<sup>2 </sup> for random effects model.
|
|
| 229 |
* This is non-zero only if Q is larger than expected under the null hypothesis that the variance is zero.
|
|
| 230 |
*
|
|
| 231 |
* <pre>
|
|
| 232 |
*
|
|
| 233 |
*
|
|
| 234 |
*
|
|
| 235 |
* sˆ2 = [Q - ( k - 1 ) ] / c
|
|
| 236 |
*
|
|
| 237 |
*
|
|
| 238 |
*
|
|
| 239 |
* </pre>
|
|
| 240 |
*
|
|
| 241 |
* where
|
|
| 242 |
*
|
|
| 243 |
* <pre>
|
|
| 244 |
*
|
|
| 245 |
*
|
|
| 246 |
*
|
|
| 247 |
* c = Max(sum_i=1ˆk w_i - [ sum_iˆk w_iˆ2 / sum_iˆk w_i ], 0)
|
|
| 248 |
*
|
|
| 249 |
*
|
|
| 250 |
*
|
|
| 251 |
* </pre>
|
|
| 252 |
*
|
|
| 253 |
* @param effectSizes
|
|
| 254 |
* @param variances
|
|
| 255 |
* @param weights
|
|
| 256 |
* @return
|
|
| 257 |
*/
|
|
| 258 | 7 |
protected double metaREVariance( DoubleArrayList effectSizes, DoubleArrayList variances, DoubleArrayList weights ) { |
| 259 |
|
|
| 260 | 7 |
if ( !( effectSizes.size() == weights.size() && weights.size() == variances.size() ) )
|
| 261 | 0 |
throw new IllegalArgumentException( "Unequal sizes" ); |
| 262 |
|
|
| 263 |
// the weighted unconditional variance.
|
|
| 264 | 7 |
double q = qStatistic( effectSizes, variances, weightedMean( effectSizes, weights ) );
|
| 265 |
|
|
| 266 | 7 |
double c = Descriptive.sum( weights ) - Descriptive.sumOfSquares( weights ) / Descriptive.sum( weights );
|
| 267 | 7 |
return Math.max( ( q - ( effectSizes.size() - 1 ) ) / c, 0.0 );
|
| 268 |
} |
|
| 269 |
|
|
| 270 |
/**
|
|
| 271 |
* Under a random effects model, CH eqn. 18-24, we replace the conditional variance with the sum of the
|
|
| 272 |
* between-sample variance and the conditional variance.
|
|
| 273 |
*
|
|
| 274 |
* <pre>
|
|
| 275 |
*
|
|
| 276 |
*
|
|
| 277 |
*
|
|
| 278 |
* v_iˆ* = sigma-hat_thetaˆ2 + v_i.
|
|
| 279 |
*
|
|
| 280 |
*
|
|
| 281 |
*
|
|
| 282 |
* </pre>
|
|
| 283 |
*
|
|
| 284 |
* @param variances Conditional variances
|
|
| 285 |
* @param sampleVariance estimated...somehow.
|
|
| 286 |
* @return
|
|
| 287 |
*/
|
|
| 288 | 0 |
protected DoubleArrayList metaREWeights( DoubleArrayList variances, double sampleVariance ) { |
| 289 | 0 |
DoubleArrayList w = new DoubleArrayList( variances.size() );
|
| 290 |
|
|
| 291 | 0 |
for ( int i = 0; i < variances.size(); i++ ) { |
| 292 | 0 |
if ( variances.getQuick( i ) <= 0 ) {
|
| 293 | 0 |
throw new IllegalStateException( "Negative or zero variance" ); |
| 294 |
} |
|
| 295 | 0 |
w.add( 1 / ( variances.getQuick( i ) + sampleVariance ) ); |
| 296 |
} |
|
| 297 |
|
|
| 298 | 0 |
return w;
|
| 299 |
} |
|
| 300 |
|
|
| 301 |
/**
|
|
| 302 |
* Weights under a fixed effects model. Simply w_i = 1/v_i. CH eqn 18-2.
|
|
| 303 |
* @param variances
|
|
| 304 |
* @return
|
|
| 305 |
*/
|
|
| 306 | 24 |
protected DoubleArrayList metaFEWeights( DoubleArrayList variances ) {
|
| 307 | 24 |
DoubleArrayList w = new DoubleArrayList( variances.size() );
|
| 308 |
|
|
| 309 | 24 |
for ( int i = 0; i < variances.size(); i++ ) { |
| 310 | 468 |
double v = variances.getQuick( i );
|
| 311 | 468 |
if ( v <= Constants.SMALL) {
|
| 312 | 0 |
v = Constants.SMALL; |
| 313 | 0 |
System.err.println( "Tiny variance " + v );
|
| 314 |
} |
|
| 315 | 468 |
w.add( 1 / v ); |
| 316 |
} |
|
| 317 |
|
|
| 318 | 24 |
return w;
|
| 319 |
} |
|
| 320 |
} |
|
||||||||||