Knowledge Accessibility and Availability in Forming Knowledge to Text Inferences Among Middle Grade Readers
Phase: NA
Conditions: Reading Problem
Sponsor: Buena Vista University

Barth, Amy Elizabeth 
 
 
1 
 
Study Protocol with Statistical Analysis Plan (SAP) 
 
 
 
Official Title of the Study:   Knowledge Accessibility and Availability in Forming 
Knowledge-to-Text Inferences among Middle Grade Readers 
 
 
NCT number:   
 
NCT03782012 
 
 
Date of the Document:   
29 August 2023 
 
 
 
 

Barth, Amy Elizabeth 
 
 
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SCIENTIFIC BACKGROUND: 
 
All major theories of reading comprehension (e.g., Kintsch, 1998; van den Broek et al., 1996) 
emphasize the importance of inferencing. Recent adolescent-based research shows that 
inferencing improves across grades 6-12, uniquely accounts for variance in sentence- and 
passage-level comprehension, and that individual differences in inferencing relate in a principled 
way to variations in reading comprehension for readers of all abilities (Barth et al., 2015b; Barnes 
et al., 2015). These findings suggest that comprehension requires inferencing and that 
comprehension fails when readers do not possess relevant knowledge (i.e., availability) or are 
slow in their retrieval (i.e., accessibility) and integration of knowledge from text or semantic 
memory during reading (Kendeou, 2015). To date, only one study has examined the effects of 
knowledge availability and accessibility on inferencing among adolescents. Those results reveal 
that students will twice as likely use easily accessible knowledge to form inferences than 
knowledge that takes longer to retrieve (Barnes et al., 1996). But this study did not measure speed 
of forming inferences, used first grade texts, and excluded less skilled middle grade readers. From 
the cognitive science literature, few studies have examined the effect of retrieval practice on 
knowledge availability and inferencing (Butler, 2010; Karpicke & Blunt, 2011; Smith & Karpicke, 
2014). Results show that retrieval practice enhances knowledge availability for text content and 
leads to improved inferencing on near and far transfer tasks. However, these studies – conducted 
on adult readers – did not measure knowledge accessibility or individual difference factors.  
 
 
OBJECTIVES: 
To extend this limited body of research, this project conducts experimental studies with three 
objectives: 
(1) To conduct experimental studies to determine the extent to which variations in 
knowledge base availability and accessibility influence the rate and accuracy of 
forming inferences.  
(2) To investigate whether individual difference factors are potential sources of variability 
in explaining inferencing and reading comprehension. 
(3) To conduct experimental studies to determine the extent to which adolescent readers 
can improve the rate and accuracy of forming inferences through retrieval practice 
techniques that have well-supported theoretical underpinnings and demonstrated 
efficacy among adults.  
 
AIMS: 
(1) To examine the extent to which knowledge-base availability and accessibility relate to 
the accuracy and rate of constructing inferences using that knowledge among middle 
grade readers.  
(2) To examine the extent to which retrieval practice (i.e., spaced practice testing) 
increases knowledge availability and accessibility and improves the accuracy and rate 
of forming inferences using that knowledge base among middle grade readers. 
(3) To integrate investigative research into an undergraduate Honors Research Program 
by developing an investigative laboratory component that engages undergraduates in 
conducting applied research.  
 
 

Barth, Amy Elizabeth 
 
 
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DESIGN: 
 
Study 1:  
 
Scientific Premise:  A reader must supply relevant knowledge and integrate current 
information from text with that knowledge (Perfetti & Stafura, 2015).  But we do not know how 
accessibility of an available knowledge base relates to knowledge-based inferencing.  Further, 
regardless of how knowledge accessibility relates to knowledge-based inferencing, other factors 
may affect the accuracy or rate at which adolescent readers form knowledge-based inferences.  
 
Participants. This study will randomly select 300 students in grades 5-8 (i.e., 160 students 
per grade). Because of the short duration of the experiment, we estimate 20% attrition. We will 
replace all students who attrite from the sample within grade to ensure sufficient power. This study 
excludes students with significant cognitive impairments who participate in the SLCSD Life Skills 
Class (e.g., severe autism, behavior, cognitive disability) due to task demands.  This study 
includes all genders, races, and socioeconomic status to enhance generalizability of findings and 
to determine if child-attributes moderate knowledge accessibility and availability.  
 
Power. General recommendations on sample sizes in structural equation modeling (SEM) 
suggest minimum samples of 300.  This sample size will allow us to detect correlations among 
constructs larger than 0.05 and regression coefficients in latent variable regressions of 0.05 with 
over 80% power.  
Method.  Participants will complete a four-phase experiment. Procedures represent a 
modification of those used by Barnes et al. (1996). In Phase 1, students learn a knowledge-base 
of 18 facts about a pretend planet named Gan. In Phase 2, which occurs after students learn the 
knowledge base to criterion (perfect recall), students will read and listen to a six-episode text. 
Immediately after hearing each text section, the computer asks students questions measuring 
understanding (i.e., literal, coherence inference, and elaborative inference questions). Phase 3 
occurs immediately after hearing all text sections and retests retention of the knowledge-base 
and inference making. One week later, Phase 4 retests the knowledge-base and inference 
making.  Students also take a larger test battery. 
Phase 1: The Knowledge Base. The knowledge base comprises 18 details that relate to the 
text. Each detail will appear on the computer screen in a block at a rate of 1 item every five 
seconds. Participants will initiate the presentation of the first detail by pressing the space bar. For 
each detail, the computer will display the fact in the middle of the tenth row of the monitor; E-
Prime (Schneider et al., 2002) will also read the detail to the student. An Immediate Recall Task 
and a Verbal Recall Task will assess knowledge base acquisition to provide an indication of how 
easily the students acquired the knowledge-base and will serve to teach the knowledge-base to 
criterion, as follows.  
Immediate Recall. The computer will ask the participant to recall as many details as he or she 
can with no time restriction on recall. We will index accessibility by the amount of time taken 
to recall the knowledge-base and availability by the total number of knowledge-base details 
correctly recalled.  
Verbal-Recall Task. Next, the computer will ask each participant 18 questions to assess his 
or her literal memory for each knowledge-based item, with each question read and presented 
in middle of the tenth row of the monitor. After completing all 18 questions, the computer will 
provide the correct answer for each question with only items that the student recalls incorrectly 

Barth, Amy Elizabeth 
 
 
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presented more than once. Presentation will stop when the participant answers all questions 
correctly. The computer will time responses to questions from the offset of the question to the 
onset of the response to provide a measure of accessibility of each knowledge-base item.  
Phase 2: Text and Questions. After the Verbal-Recall Task, the computer will present the six-
section text, one section at a time. Seven questions asked immediately after each text section 
assess various aspects of text comprehension (literal questions, coherence inference questions, 
and elaborative inference questions). The computer will time responses to questions from the 
offset of the question to the onset of the response to provide a measure of accessibility of each 
item. When a student answers a question incorrectly or incompletely, the research assistant will 
use a nonspecific prompt to elicit a fuller response (i.e., tell me more about that).  
Phase 3:  Retention of the Knowledge Base. After the student completes all text sections and 
questions, the computer will test memory for the knowledge-base using the Immediate Recall 
Task and Verbal Recall Task described for Phase 1 with no feedback provided.  
Phase 4:  Long-Term Retention of the Knowledge Base. One week later, students’ retention 
of the knowledge-base will be tested using the Immediate Recall Task and Verbal Recall Task 
described for Phase 1. We will also administer additional measures to assess reading 
comprehension, inferencing, and individual difference factors.  
 
Assessments. Assessments measure the constructs of reading comprehension, inferencing, 
word reading efficiency, metacognition, working memory, and background knowledge.  
 
 
Statistical Analysis Plan for Study 1.  
 
Data Analysis.  We will screen for missing data and outliers and evaluate the distributional 
properties of observed variables, making transformations as necessary and appropriate.  If 
possible, we will correlate non-plausible values or list them as missing if not possible, and label 
extreme data points.  
 
Analytic Approach.  We will model the effects of knowledge availability and accessibility on 
inferencing without dichotomizing the distribution of comprehension.  To determine whether 
reader characteristics (i.e., knowledge availability and accessibility, metacognition, reading 
comprehension, word reading efficiency, background knowledge, working memory, and grade) 
make unique contributions to inferencing, we will fit mixed effects explanatory item response 
models to the trial-by-trial inferencing accuracy and speed data using SAS PROC MIXED with 
item-level accuracy and reading speeds cross classified between person and items.  We will also 
next people within grade, treating grouping variable for people such as grade and items as fixed 
factors.  If limited variability exists in the accuracy data, we will only model response time data.   
The sampling plan maximizes power to detect whether variations in knowledge accessibility and 
availability relate to differences in their rate and accuracy in which students use that knowledge 
to form inferences.  The study has sufficient power to test secondary hypotheses which will 
examine if accessibility of knowledge affects inferencing with that knowledge more so for less 
skilled than for skilled comprehenders after controlling for knowledge availability and whether 
individual difference factors such as working memory, metacognition, and reading fluency relate 
to differences in the accuracy and rate of forming knowledge-based inferences and 
comprehension of text.  
 
 

Barth, Amy Elizabeth 
 
 
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Study 2: 
 
Scientific Premise.  In the transfer literature, some evidence suggests that conditions of 
initial learning improve the direction and magnitude of transfer.  For example, several studies 
show that the greater the degree of initial learning, the higher the probability of positive transfer 
(e.g., Bruce, 1933; see Ellis, 1965) as does increasing the quantity and variability of training 
question types or problems (see Kimball & Holyoak, 2000).  These findings suggest that if a 
student receives multiple opportunities and ways to access information in memory, it increases 
retention of the information and accessibility to the information which can improve use of that 
knowledge on related tasks.  To date, no study has evaluated how initial learning conditions 
designed to enhance knowledge availability and accessibility effect knowledge-based inferencing 
and comprehension among middle grade less skilled readers. 
 
Participants.  Study participants (n – 180) will come from Storm Lake Community School 
District students in grades 5-8.  We anticipate that students will come from diverse socio-economic 
and ethnic backgrounds.   
 
Power and Design.  We estimate the sample associated with an effect size of 0.25, alpha 
0.05, and with over 80% power at 136 participants for between group differences, 36 for within 
group differences, and 180 for the interaction.  Randomization will occur within grade, with all 
qualified students in grade 5 available for randomization because they did not participate in Study 
1.  
Procedure.  Study 2 follows the same procedure as Study 1 with the following changes.  
After the Verbal-Recall Task, the computer will present the six-section informational text one 
section at a time with each section approximately 500 words in length.  Immediately after studying, 
the computer reassesses the students’ retention of the knowledge base with the Immediate Recall 
Task and Verbal Recall Task.  Next, students will restudy two of the text sections (restudy 
passages condition), repeatedly take the same test on another two text sections (same test) and 
repeatedly take different tests on the other two text sections (variable text).  Immediately following, 
students’ retention of the knowledge-base will be reassessed with the Immediate Recall and 
Verbal Recall Tasks. 
 
Assessments.  One week later, participants will return to assess their knowledge base 
retention and inferencing and comprehension of the passages. Study 1 assessments will also be 
administered.  
 
 
 
 

Barth, Amy Elizabeth 
 
 
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Statistical Analysis Plan for Study 2.  
 
 
Data analysis.  We will screen for missing data and outliers and evaluate the distributional 
properties of observed variables, making transformations as necessary and appropriate.  When 
possible, we will correct non-plausible values or list them as missing if we cannot correct them 
and label them extreme data points.  
 
 
Analytic approach.  Data analysis will use repeated measures analysis of variance 
models to examine the effect of the experimental condition on knowledge retention.  Separate 
ANOVAS will analyze scores obtained on the question types and the efferent error types by 
condition.  The sampling plan maximizes power to examine Aim 2.  The analyses include factors 
such as socioeconomic, gender, and disability status to determine whether these demographic 
factors impact inferencing.