Convergence= and Iterations= control the number of iterations performed. Write=Yes writes the details reported on screen into Table 2. The number of iterations required depends on how difficult it is to obtain good estimates from the data. Many iterations may be required if
1) there is a poor fit of the data to the Rasch model.
2) the element parameter distribution is badly skewed or multi-modal.
3) there are rarely observed response categories.
4) exceedingly precise Convergence= criteria have been specified.
5) the data matrix is composed of disjoint subsets of observations, e.g., boys rated by Judge A, but girls by Judge B. When this is detected, a warning message is displayed.
Table 3. Iteration Report.
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| Iteration Max. Score Residual Max. Logit Change |
| Elements % Categories Elements Steps |
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| PROX 1 .7405 |
| JMLE 2 26.6978 22.2 29.9588 .3374 .9902 |
| JMLE 3 22.4284 13.4 27.3399 -.1155 1.0049 |
| JMLE 4 11.0189 6.6 22.0935 -.0514 .9957 |
| JMLE 5 -3.5380 -2.9 9.5224 -.0304 -.7481 |
| JMLE 6 -5.7141 -4.8 2.6727 -.0620 -.2008 |
| JMLE 7 -4.5692 -3.4 1.8210 .0501 -.0892 |
| JMLE 8 -3.5327 -2.5 1.4746 .0393 -.0599 |
| JMLE 9 -2.7709 -1.9 1.2091 .0314 -.0529 |
| JMLE 10 -2.1980 -1.4 .9963 .0255 -.0446 |
| JMLE 11 -1.7600 -1.1 .8245 .0209 -.0371 |
| JMLE 12 -1.4209 -.9 .6847 .0172 -.0309 |
| JMLE 13 -1.1553 -.7 .5703 .0143 -.0258 |
| JMLE 14 -.9451 -.6 .4761 .0119 -.0215 |
| JMLE 15 -.7771 -.5 .3982 .0099 -.0180 |
| JMLE 16 -.6418 -.4 .3336 .0083 -.0151 |
| JMLE 17 -.5319 -.3 .2798 .0069 -.0127 |
| JMLE 18 -.4422 -.3 .2349 .0058 -.0106 |
| JMLE 19 -.3685 -.2 .1974 .0049 -.0089 |
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Subset connection O.K.
Iteration counts the number of times the data has been read.
PROX is the "normal approximation algorithm" to obtain approximate estimates speedily. Steps are not estimated during PROX.
JMLE is joint (unconditional) maximum likelihood estimation to obtain precise estimates.
Facets generally produces its results with high precision. This precision is rarely needed in practice before the final runs. There are several ways to lower the precision of the results. Most immediately, Ctrl+F forces Facets to move into the reporting phase at the end of the current iteration through the data. Other specifications include Iterations= and Convergence=. Inspection of the iterations, Table 3 of the output, indicates when the changes per iteration are too small to have any important meaning at the current stage of your analysis. Here this happens after just 4 iterations.
Max. Score Residual
Elements: the largest difference (residual), in score points, between the observed and expected score corresponding to any element's parameter estimate. 1.0 is the smallest observable (i.e., in the data) difference with the standard model weighting of 1.
%: the largest residual as a percent of the (maximum possible score - minimum possible score) for any element.
Categories: the largest difference between the observed and expected counts of occurrence corresponding to any category of a rating scale (or partial credit). 1.0 is the smallest observable difference with the standard model weighting of 1.
Recount required
when this appears, it means that the scores corresponding to some element parameters had extreme values (either 0 or the maximum possible). These parameters are dropped from estimation, forcing a recount of the marginal scores of the other elements.
Max. Logit Change
Elements: the largest change, in logits, between any element parameter estimate this iteration and its estimate the previous iteration. Starting estimates are either 0.0 logits, or the values given in the specification file.
Categories: the largest change, in logits, between any step parameter estimate this iteration and its estimate the previous iteration. Starting estimates are either 0.0 logits, or the values given in the specification file.
After the first few iterations, both "Max. Score Residual" and "Max. Logit Change" should steadily reduce in absolute size, i.e., draw closer to zero. There may be occasional perturbations due to unusual data. If the iterative procedure seems to have reached a plateau, you may force termination by pressing the Ctrl+"S" keys simultaneously.
The more detailed iteration report, which appears on your screen, can be recorded in your output file with a "Write=Yes" specification
Subset connection O.K.
Facets has verified that all measures can be estimated in one, unambiguous frame of reference. Warning messages here require investigation.
