# Rasch Analysis

Rasch analysis can be applied to assessments in a wide range of disciplines, including health studies, education, psychology, marketing, economics and social sciences.

Many assessments in these disciplines involve a well defined group of people responding to a set of items for assessment. Generally, the responses to the items are scored 0, 1 (for two ordered categories); or 0, 1, 2 (for three ordered categories); or 0, 1, 2, 3 (for four ordered categories) and so on, to indicate increasing levels of a response on some variable such as health status or academic achievement. These responses are then added across items to give each person a total score. This total score summarise the responses to all the items, and a person with a higher total score than another one is deemed to show more of the variable assessed. Summing the scores of the items to give a single score for a person implies that the items are intended to measure a single variable, often referred to as a unidimensional variable.

The Rasch model is the only item response theory (IRT) model in which the total score across items characterizes a person totally. It is also the simplest of such models having the minimum of parameters for the person (just one), and just one parameter corresponding to each category of an item. This item parameter is generically referred to as a threshold. There is just one in the case of a dichotomous item, two in the case of three ordered categories, and so on.

1.   What is Rasch Analysis

2.   Why undertake a Rasch analysis?

3.   The research paradigm and the Rasch model

4.   Is there more than one Rasch model?

5.   Different Rasch Model Specifications

6.   Thresholds and Steps

7.   Disordered Thresholds as an Anomaly

8.   Who should use a Rasch analysis?

9.   An ideal approach to a Rasch analysis

10. Recommended Rasch Software

11. The RUMM approach to Rasch Analysis

12. What courses and workshops are available on Rasch analysis?

## Cloud Rasch Analysis Engine & APIs

Rumlab and Timewatch have developed a cloud based rasch analysis engine and APIs which allow anyone to take full advantage of the power of the Rasch engine, with out the need to understand or implement the complex mathematics involved.

The system allows for data and test instrument setup data (created via Rumm2030 or any other means) to be transmitted securely via SSL to a cloud server, with resultant data securely returned. The cloud servers do store customer setup data, test or result data, and we recommend that data passed to the servers be anonymous or utilize random reference id's so that only the entity calling the service can interpret the meaning of the data and the result.

### Rasch Analysis API's

Although the Rasch Cloud Server can provide a test page for customers to upload their test instrument data (item's, item labels, thresholds etc.), this is provided to demonstrate how with purely instrument data a fully responsive web application that can support PCs, Macs, Phones and Tablets in portrait or landscape mode can support real time testing and demonstrate the speed and versatility of the Rasch Analysis engine as resultant data is displayed on the test page. The intention is that developers that wish to create their own Test or Questionnaire sustems can do so, but can securely utlize our Rash Analysis API's to analyze their data and provide resultant test scores.