### How Do Changes in Standard Deviation Affect Sample Size Estimation?

The standard deviation is the most common way of measuring variability or “dispersion” in data. The more the data is dispersed, the more measures such as the mean will fluctuate from sample to sample. That means higher variability (higher standard deviations) requires larger sample sizes. But exactly how much do standard deviations—whether large or small—impact

### Sample Sizes for Comparing Rating Scale Means

Are customers more satisfied this quarter than last quarter? Do users trust the brand less this year than last year? Did the product changes result in more customers renewing their subscriptions? When UX researchers want to measure attitudes and intentions, they often ask respondents to complete multipoint rating scale items, which are then compared with

### Sample Sizes for Comparing Dependent Proportions

Sample size estimation is an important part of study planning. If the sample size is too small, the study will be underpowered, meaning it will be incapable of detecting sufficiently small differences as statistically significant. If the sample size is too large, the study will be inefficient and cost more than necessary. A critical component

### Does Removing the Neutral Response Option Affect Rating Behavior?

Many topics about the design of rating scales can provoke strong opinions and heated debates. The arguments include whether or not scales should include a neutral response. Unlike rating scales with an even number of points (e.g., 4, 6, or 10), rating scales with an odd number of points (e.g., 5, 7, or 11) contain

### Initial Validation of Tech-Savvy Measures

How do you measure tech savviness? For several years (since 2015), we’ve been on a mission to develop a valid and practical measure. In our earlier articles, we have Reviewed the literature. We reviewed the literature on tech-savvy measures and found three key approaches to measuring tech-savviness by assessing (1) what a person knows, (2)

### How to Estimate the Standard Deviation for Rating Scales

The standard deviation is the most common measure of variability. It’s less intuitive than measures of central tendency such as the mean, but it plays an essential role in analysis and sample size planning. The standard deviation is a key ingredient when building a confidence interval and can be easily computed from a sample of

### Refining a Tech-Savvy Measure for UX Research

In an earlier article, we described a pilot study from 2015 in which we investigated how to measure tech savviness. Building on the published literature, we generated candidate items that measured three aspects of tech savviness: what people know, what people do, and what people feel. In that pilot study, we assessed knowledge using a

### In Search of a Tech-Savvy Measure for UX Research

How do you measure tech savviness? Abstract constructs such as usability, trustworthiness, intelligence, and desirability can be difficult to measure. The same applies to tech savviness. But to paraphrase Potter Stewart, we know a tech-savvy person when we see one. Tech savviness should matter to UX researchers. When we measure an experience, we don’t want

### Four Ways to Pick the Right UX Method

User experience research has many methods. Some methods, such as usability testing, are used frequently and have been around for decades. Other, more recent additions, such as click testing, are useful variations on existing methods. Selecting the right UX method means narrowing down the available methods to those that will address (1) the primary research