Select and operationally define the data you need to collect, and decide what type of information you want reported when the assessment is scored. Operational definitions are the specific definitions for key terms in your data and add reliability to your assessment. .
Select the type of instrument to be developed. A rating scale or Likert scale is most commonly used when trying to determine a person's perspective or agreement with a proposed statement or question. Each number in the scale is assigned a point value which allows the rater to create a total score, thus allowing for comparison amongst individuals tested.
Collect reliability data by determining the procedure you will use to estimate it, such as interobserver reliability, test-retest reliability and internal consistency. Depending on the type of instrument you have selected, reliability data will be the key component to ensuring standardization in your assessment tool.
Analyze the validity of the assessment tool by studying the meaningfulness and relevance of the operational definitions of your data. An assessment should have a purpose and should allow for a credible outcome.
Create a list of instructions to follow each and every time the assessment is administered, scored, and interpreted. This creates a standardized assessment so that anyone who uses the assessment tool can do so and maintain validity and reliability.
Use a computer program such as a spreadsheet or blank document to create a template for the instrument you have chosen to develop.
Create and write a title for your assessment tool that is clear and concise.
Write your list of specific instructions to be followed beneath the title of your assessment tool.
Develop and write your assessment tool's questions. Keep in mind that the questions must use operational definitions and must be reliable and valid.
Define what the point values mean if using a rating scale instrument.
Use your template as a guide to create a final copy of your assessment tool. The final copy does not include the standardized instructions and should only include the questions proposed to the group you are assessing.
Pretest the assessment tool by choosing a sample group with similar characteristics as the group for which you will be collecting data.
Test for reliability and validity of your assessment tool by pretesting the instrument three times with various groups.
Administer the assessment tool to the intended group.