[Rasch] Questions about interpreting wright/item map for rating scale model

Yingchen 2596011329 at qq.com
Tue Jul 21 18:31:33 AEST 2020

Dear Rasch lovers:
    Can someone tell me how to interprete the wright/item map for the rating scale model? I attached the graph  from jMetrik. 
    I read user's manual for jMetrik, some publications and tutorials on item map and checked the estimated item values. I could understand the map with histogram on the left and dots on the right, but not this graph. I checked and thought the graph was produced correctly. 
   Would appreciate if anyone can help with the following questions.
  Q1: What do the lines mean? They must represent the item parameter estimates. However, I cannot align them with the item file. 
  Q2: What do the different shapes on the lines represent? There are squares, diamonds,circles, rectangles, arrows, arrows pointing to different directions. My guess is that the software developers used different shapes to enable readers to tell the different items. 
  Q3: What do the square and the circle in the middle of the last two lines represent?  I know that they should have something to do with the item parameter estimates. 
  Q4: is the length of each line related to confidence interval of item parameter estimate? 
  Q5. Can anyone recommend non-commerical softwares with the capacity to produce the the item map? 

  BTW, I did send a message to jMetrik help 2 days ago, but there was no reply.
  Any help is greatly appreciated. 
  Thank you for your time and attention. 

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