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2 Making the MDM file. For any given set of variables, you only need to do this once. But if you need to add a variable, you will need to repeat the process. HLM cannot transform variables (e.g., a square of a variable), so if you need a transformed variable in your analysis, it must be included in the set of variables read into HLM.
ASCII Input is a text file. Stat Package Input is easier. With the student version, use SPSS.sav files. With the regular version Excel files can be read. 3
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5 As far as I can tell, selecting measures within persons just changes the notation in the GUI. More on missing data at the end of the handout.
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Clicking Browse opens a WINDOWS dialog Box 7
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10 This is a fragment of the level-1 file that will be read into HLM. I included it so you can see what the file looks. It would not be displayed in the process of creating the mdm file. The variable named ID a school (level-2 unit). It need not be called ID. Note that the file is sorted by ID.
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17 This is a fragment of the level-2 file that will be read into HLM. I included it so you can see what the file looks. It would not be displayed in the process of creating the mdm file. The variable named ID is a school (level-2 unit). It need not be called ID. Note that the file is sorted by ID and includes the mean of SES.
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Clicking Save mdmt file opens a WINDOWS dialog Box 22
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This screen is displayed for a few seconds. 26
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28 These results should be compared with the descriptive statistics produced by SPSS from the files you read into HLM. If there is not agreement, something may have gone wrong in reading the data. This a Notepad file. You may want to save this file under a new name for future reference.
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The >> << indicates that the level-1 variables are showing. After selecting level- 1 variables for the model, clicking level-2 displays the level-2 variables 30
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This operation is optional 33
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This operation is optional 35
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Produces a Windows dialog box to save your program. 38
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40 This box will flash by indicating the program is running. After it runs click file and view output
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Creating a new model from an old mdm file 42
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You can create a new model 45
Running an old model or revising an old model 46
You can re-run or revise the existing model. 47
You can edit an existing file. This can be useful if you work on different machines and the drive labels vary across the machines. However if the drive labels change across machines, the GUI will give you error messages and you can change the labels through the GUI. 48
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50 This is an example of the GUI when persons-within-measures is selected. See page 5 Note the change in the notation. Compare to page 33.
51 How HLM handles Missing Data HLM2 handles missing data at level-1 of the hierarchy as follows: Observations with missing data will be deleted using listwise deletion at either the MDM creation stage or when the analysis is run. The Make MDM dialog box for 2-level (HLM2) allows the chooser to two between these options. If deletion at the MDM creation stage is chosen, listwise deletion is performed based on the level-1 variables selected for inclusion in the MDM file. Listwise deletion means that if there were any missing scores in a row of the SPSS level-1 file on the variables selected
52 inclusion in the MDM file, that row of data will be deleted when the MDM file is created. If deletion at the analysis stage is chosen, listwise deletion is performed based on the variables included in the actual model to be run. Listwise deletion means that if there were any missing scores in a row of the SPSS level-1 file on the variables selected inclusion in the analysis, that row of data will be deleted when the analysis is conducted. Clearly deletion at the analysis stage is the better option. Failure to acknowledge missing data. If you have missing data but do not select yes, you get this message Missing data found at level-1, unable to continue. Non-matching Levl-1 and Level-2 Files If you have cases in the level-1file for which there is not a matching ID in the level-2 file, the ids without the match will be deleted and the deleted ids will be identified in the file that is displayed when you click check stats: Group Group Group 52 not in level-2 file. 173 not in level-2 file. 180 not in level-2 file.
If you have cases in the level-2 file for which there is not matching ID in the level-1, the ids without the match will be deleted but there is no listing of the ids that are deleted. 53