Meaningful Change for PROMIS^®

Estimates for the magnitude of change that corresponds to “important” change depend on if you are comparing groups or monitoring an individual.

 [KFC1]Kozlowski AJ, Cella D, Nitsch KP, Heinemann AW. Evaluating Individual Change

What is meaningful change?

When you compare two or more groups’ scores, even trivial differences can be statistically significant if the sample size is large. However, that statistically significant difference may not be a clinically important difference. We want to know the amount of change that patients would perceive as real improvement or worsening that would justify a change in clinical management or support a claim of treatment benefiting or harming a person.

Therefore, you should identify if the magnitude of change you see has met the threshold to be considered meaningful.

Comparing Groups Versus an Individual

Identify if you are comparing groups of people or one person over time. The magnitude of change that is considered meaningful varies depending on who you are comparing.

Group comparisons include:

• Assessing two or more groups and determining if the difference between the groups’ means reaches a magnitude patients consider meaningful (“between-group difference”).
  • E.g., Group A’s PROMIS Physical Function is 60. Group B’s Physical Function is 64. Is the difference between these two groups meaningful?
• Assessing a single group of patients over time and determining if the difference in means between two time points reaches a magnitude that patients consider meaningful (“within-group change”).
  • E.g., the mean PROMIS Fatigue score for a group of people worsened from 55 to 60. Is this worsening meaningful?

For an individual:

• Determining if a person has improved or deteriorated (“within-person change”).
  • E.g.: A patient’s Anxiety score improved from 65 to 58 two months later. Is this improvement real and meaningful?

PROMIS Group Change

For group-level comparisons, a difference of 2 to 6 PROMIS T-score points suggests meaningful change.

The range to evaluate between-group difference or within-group change is generally between 2 and 6 points (Terwee et al., 2021). A threshold of 3 T-score points may be reasonable for most contexts. This guidance applies to PROMIS short forms, computer adaptive tests (CATs), profiles, and scales.

PROMIS Individual Change

For a single individual, a change of 5 to 7 PROMIS T-score points suggests meaningful change.

The range to evaluate within-person change over time generally ranges between 5 and 7 PROMIS T-score points. A lower bound of 5 PROMIS T-score points may be reasonable for most contexts. This applies to PROMIS short forms, computer adaptive tests (CATs), profiles, and scales.

Guidance for Selecting Meaningful Change Thresholds

Evidence continues to accumulate regarding reasonable estimates of meaningful change score thresholds. There are several things you should keep in mind when using these estimates.

• There is no single number that reflects a meaningful or important change for all patients in all circumstances for all purposes.
• There are different methods for calculating change thresholds (see Meaningful Change Methods) and they will yield different estimates. Also, analyses in different samples and contexts will lead to different estimates. Compile results from multiple studies.
• Selecting a value requires a judgment on your part. You should consider, for example, the use of the value. Estimates on the lower end of the reported important change range (for example, Minimally Important Difference [MID], Minimally Important Change [MIC], Minimal Clinically Important Difference [MCID]) might be appropriate for group comparisons. A higher estimate is more appropriate to categorize change in an individual (within-person change). Consider the consequences of how the estimate will be used (e.g., what is the cost-benefit ratio of a lower versus a higher threshold for a given context). Evaluate the relative risk of missing people who had meaningful change but were below the selected threshold versus identifying people as having experienced meaningful change when they did not (false positives).
• Values for improvement may vary from values for deterioration.
• Finally, you should keep in mind that most estimates of meaningful or important change are an average across the range of scores from a group of patients. It may be that people require more or less change to consider it meaningful depending on where they started. In addition, especially in the context of clinical monitoring of individuals, an average score may or may not be considered important to any given individual person.

In summary, to select a threshold for comparing scores:

1. Identify how you will use the threshold.
2. Triangulate available data (e.g., recommended thresholds on HealthMeasures.net, published studies).
3. Use your judgment.