Purpose: The lack of a definite standard for determining the sample size in qualitative research leaves the research process to the initiative of the researcher, and this situation overshadows the scientificity of the research. The primary purpose of this research is to propose a model by questioning the problem of determining the sample size,…

Despite recent methodological advances in saturation, guidelines for its estimation in more complex research designs--such as ethnographic studies--have been lacking. We present an accessible, step-by-step approach to empirical assessment of data saturation, tested on a moderately sized ethnographic study with 109 combined direct observations and…

The multistage testing (MST) design has been gaining attention and popularity in educational assessments. For testing programs that have small test-taker samples, it is challenging to calibrate new items to replenish the item pool. In the current research, we used the item pools from an operational MST program to illustrate how research studies…

The product Bayes factor (PBF) synthesizes evidence for an informative hypothesis across heterogeneous replication studies. It can be used when fixed- or random effects meta-analysis fall short. For example, when effect sizes are incomparable and cannot be pooled, or when studies diverge significantly in the populations, study designs, and…

Not knowing the population size is a common problem in data-limited contexts. Drawing on work in Sierra Leone, this short take outlines a four-step solution to this problem: (1) estimate the population size using expert interviews; (2) verify estimates using interviews with participants sampled; (3) triangulate using secondary data; and (4)…

In statistics classes, the central limit theorem has been demonstrated using simulation-based illustrations. Known population distributions such as a uniform or exponential distribution are often used to consider the behavior of the sample mean in simulated samples. Unlike such simulations, a number of real-data-based simulations are here…

Expected yield rates are essential to a survey's data collection plan, as they inform requisite sample sizes to meet the survey's objectives. Given an overall expected yield rate for a self-administered mail survey, this short take describes a simple method for using the Census Planning Database to assign differential yield rates to lower-level…

Qualitative research sample size determination has always been a contentious and confusing issue. Studies are often vague when explaining the processes and justifications that have been used to determine sample size and strategy. Some provide no mention of sampling at all, whilst others rely too heavily on the concept of saturation for determining…

The results of total testing from the years 2015-2022 on the mathematical and verbal achievement of Lithuanian pupils (N [approximately equal to] 250,000) are presented. These are the standardised tests from grades 4 to 12. The K-Means method has discovered six types of achievement. The highest achievement type is dominated by girls (61.1%) who…

The authors discuss the use of surveys for collecting data from a population sample and emphasise the importance of being careful with the language of data collection. [For "The Data Files 5: Graphs for Exploring Relationships," see EJ1355504.]

Photovoice involves respondents taking photographs of their environment to promote critical discussions and reflect on their experiences. Photovoice empowers marginalized communities and serves to reach policymakers. The Arizona Youth Identity Project (AZYIP) used photovoice with an innovative approach in a multisite research design with a large…

Thanks to COVID-19, schools were closed and tests were canceled. The result is that we may not see test-taking data typically seen before. For some analyses, sample sizes may not meet the minimum requirement. For others, the sample of test-takers may be different from previous years. In some situation, there may be no data at all. What do we do in…

Randomized experiments involving education interventions are typically implemented as cluster randomized trials, with schools serving as clusters. To design such a study, it is critical to understand the degree to which learning outcomes vary between versus within clusters (schools), specifically the intraclass correlation coefficient. It is also…

This appendix supplements the report "Stackable Credential Pipelines in Ohio: Evidence on Programs and Earnings Outcomes" (ED613593). In the appendix, the authors provide more details about the data and empirical approach, additional information about the samples, and some alternative results from analyses related to those that appear in…

The Student Evaluation of Teaching (SET) instrument provides insight for instructors and administrators alike, often touting high response-rates to endorse their validity and reliability. However, response-rate alone omits consideration for "adequate quantity of 'observational sampling opportunity' (OSO) data points" (e.g., high student…