What causes low reliability?

What causes low reliability?

The difficulty level and clarity of expression of a test item also affect the reliability of test scores. If the test items are too easy or too difficult for the group members it will tend to produce scores of low reliability. Because both the tests have a restricted spread of scores.

In which type of data precaution is highly required?

secondary data

What is the minimum acceptable level of reliability?

A general accepted rule is that α of 0.6-0.7 indicates an acceptable level of reliability, and 0.8 or greater a very good level. However, values higher than 0.95 are not necessarily good, since they might be an indication of redundance (Hulin, Netemeyer, and Cudeck, 2001).

What is the range of reliability?

The values for reliability coefficients range from 0 to 1.0. A coefficient of 0 means no reliability and 1.0 means perfect reliability. Generally, if the reliability of a standardized test is above . 80, it is said to have very good reliability; if it is below . 50, it would not be considered a very reliable test.

Why is split-half reliability important?

Because it arises from consistency between parts of a test, split-half reliability is an “internal consistency” approach to estimating reliability. This result is an estimate of the reliability of the test scores, and it provides some support for the quality of the test scores.

How do you increase the reliability of a survey?

If people respond to the survey questions the second time in the same way they remember responding the first time, this will give an artificially good impression of reliability. Increasing the time between test and retest (to reduce the memory effects) introduces the prospect of genuine changes over time.

Which of these two sets of data is more reliable and why?

Primary data are more reliable and suitable for the enquiry because it is collected for a particular purpose. It is less reliable and less suitable as someone else has collected the data which may not perfectly match our purpose. Collecting primary data is quite expensive both in time and money terms.

What is the relationship of Cronbach’s alpha reliability to split-half reliability?

A famous description of Cronbach’s alpha is that it is the mean of all (Flanagan–Rulon) split-half reliabilities. The result is exact if the test is split into two halves that are equal in size. This requires that the number of items is even, since odd numbers cannot be split into two groups of equal size.

Why is primary research more reliable?

Primary research tools and data can become more authentic if the methods chosen to analyze and interpret data are valid and reasonably suitable for the data type. . Primary sources are more authentic because the facts have not been overdone. Reliability improves with using primary data.

Which data is more reliable and why?

Answer: Primary data are more reliable than secondary data. It is because primary data are collected by doing original research and not through secondary sources that may subject to some errors or discrepancies and may even contain out-dated information.

How do you use split-half reliability?


  1. Administer the test to a large group students (ideally, over about 30).
  2. Randomly divide the test questions into two parts. For example, separate even questions from odd questions.
  3. Score each half of the test for each student.
  4. Find the correlation coefficient for the two halves.

Is Cronbach alpha 0.5 reliable?

If you try all your other means to improve Cronbach Alpha to > 0.7, you can cite this book – see below book’s title & author names as well as Cronbach Alpha 0.5 as moderate reliability.

What is a good alpha reliability?

The alpha coefficient for the four items is . 839, suggesting that the items have relatively high internal consistency. (Note that a reliability coefficient of . 70 or higher is considered “acceptable” in most social science research situations.)

Why is primary data more reliable?

Primary data is very reliable because it is usually objective and collected directly from the original source. It also gives up to date information about a research topic compared to secondary data. It doesn’t take so much time and most of the secondary data sources can be accessed for free.