Analyzing Age-Period-Cohort Data: A Review and Critique

2019 ◽  
Vol 45 (1) ◽  
pp. 467-492 ◽  
Author(s):  
Ethan Fosse ◽  
Christopher Winship
Keyword(s):  
General Framework ◽  
Multilevel Models ◽  
Verbal Ability ◽  
Partial Identification ◽  
Equality Constraints ◽  
Sensitivity Analyses ◽  
Proxy Variables ◽  
Step Procedure ◽  
Constraints Model ◽  
General Step

Age-period-cohort (APC) analysis has a long, controversial history in sociology and related fields. Despite the existence of hundreds, if not thousands, of articles and dozens of books, there is little agreement on how to adequately analyze APC data. This article begins with a brief overview of APC analysis, discussing how one can interpret APC effects in a causal way. Next, we review methods that obtain point identification of APC effects, such as the equality constraints model, Moore-Penrose estimators, and multilevel models. We then outline techniques that entail point identification using measured causes, such as the proxy variables approach and mechanism-based models. Next, we discuss a general framework for APC analysis grounded in partial identification using bounds and sensitivity analyses. We conclude by outlining a general step-by-step procedure for conducting APC analyses, presenting an empirical example examining temporal shifts in verbal ability.

scholarly journals School Readiness Assessments for Class Placements and Academic Sorting in Kindergarten

2018 ◽  
Vol 34 (3) ◽  
pp. 518-547 ◽  
Author(s):  
F. Chris Curran ◽  
Michael H. Little ◽  
Lora Cohen-Vogel ◽  
Thurston Domina
Keyword(s):  
Language Arts ◽  
School Readiness ◽  
English Language ◽  
Multilevel Models ◽  
Kindergarten Readiness ◽  
Academic Ability ◽  
Sensitivity Analyses ◽  
Policy And Practice ◽  
Placement Decisions ◽  
Class Placement

Kindergarten readiness assessments are commonly used in schools nationwide. Prior work shows that the use of such assessments for class placement decisions has increased in recent years. This article uses the Early Childhood Longitudinal Study of 2011 to explore whether the use of readiness assessments for such purpose predicts differential sorting of students across classrooms by prior academic ability. Results from multilevel models as well as other sensitivity analyses suggest that the use of readiness assessments for classroom placements is predictive of slightly higher cross-class ability sorting, particularly in English/language arts. The implications for policy and practice are discussed.

scholarly journals Age modification of the relationship between C-reactive protein and fatigue: findings from Understanding Society (UKHLS)

2017 ◽  
Vol 48 (8) ◽  
pp. 1341-1349 ◽  
Author(s):  
A. Hughes ◽  
M. Kumari
Keyword(s):  
Multilevel Models ◽  
Inflammatory Marker ◽  
Glycated Haemoglobin ◽  
Clinical Disease ◽  
Sensitivity Analyses ◽  
Older Individuals ◽  
Community Studies ◽  
C Reactive Protein ◽  
Adult Age ◽  
Reactive Protein

AbstractBackgroundSystemic inflammation may play a role in the development of idiopathic fatigue, that is, fatigue not explained by infections or diagnosed chronic illness, but this relationship has never been investigated in community studies including the entire adult age span. We examine the association of the inflammatory marker C-reactive protein (CRP) and fatigue assessed annually in a 3-year outcome period for UK adults aged 16–98.MethodsMultilevel models were used to track fatigue 7, 19, and 31 months after CRP measurement, in 10 606 UK individuals. Models accounted for baseline fatigue, demographics, health conditions diagnosed at baseline and during follow-up, adiposity, and psychological distress. Sensitivity analyses considered factors including smoking, sub-clinical disease (blood pressure, anaemia, glycated haemoglobin), medications, ethnicity, and alcohol consumption.ResultsFatigue and CRP increased with age, and women had higher values than men. CRP was associated with future self-reported fatigue, but only for the oldest participants. Thus, in those aged 61–98 years, high CRP (>3 mg/L) independently predicted greater fatigue 7, 19, and 31 months after CRP measurement [odds ratio for new-onset fatigue after 7 months: 1.88, 95% confidence interval (CI) 1.21–2.92; 19 months: 2.25, CI 1.46–3.49; 31 months: 1.65, CI 1.07–2.54]. No significant longitudinal associations were seen for younger participants.ConclusionsOur findings support previously described CRP–fatigue associations in older individuals. However, there are clear age modifications in these associations, which may reflect a contribution of unmeasured sub-clinical disease of limited relevance to younger individuals. Further work is necessary to clarify intervening processes linking CRP and fatigue in older individuals.

Increasing Test Utility through Teacher-Identification of Criterion Components

1964 ◽  
Vol 15 (3) ◽  
pp. 979-983 ◽  
Author(s):  
Robert Perloff
Keyword(s):  
Step Procedure ◽  
Educational Tests ◽  
General Step

A factor-analytically oriented method is proposed for increasing the utility of educational tests through an explicit identification of criterion components against which predictor elements might be evaluated. A hypothetical illustration is provided, along with a general step-by-step procedure for accomplishing the objectives specified.

scholarly journals P664 Adherence to mesalazine and identification of patients with ulcerative colitis in healthcare administrative databases of Tuscany (Italy)

2021 ◽  
Vol 15 (Supplement_1) ◽  
pp. S588-S589
Author(s):  
L Bertani ◽  
C Bartolini ◽  
S Ferraro ◽  
I Convertino ◽  
S Giometto ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Medication Possession Ratio ◽  
Study Data ◽  
Sensitivity Analyses ◽  
Administrative Databases ◽  
Statistical Measures ◽  
Step Procedure ◽  
Bowel Diseases ◽  
Inflammatory Bowel

Abstract Background Drug supply can be used to identify patients with a specific disease in healthcare administrative databases (HAD), particularly when they have a univocal indication. For drugs with multiple indications, other elements must be considered, such as dosing or scheduled regimen. This is the case of mesalazine (MZ), a drug indicated for ulcerative colitis (UC), but also for Crohn’s disease and other not classifiable inflammatory bowel diseases. The aim of the present study was to explore adherence trajectories to MZ, in the attempt of identifying variables useful to detect patients with UC in HAD Methods In this retrospective cohort study, data was retrieved from administrative healthcare databases in Tuscany. Patients who had at least a first MZ dispensation between 6/1/2011 and 6/30/2016 (index date, ID) were included. We performed four sub-group analyses: 1) Patients with at least 1 MZ dispensation in the follow-up (FUP); 2) Patients with at least 2 MZ dispensations in the first 3 months of FUP; 3) Patients with MZ dosage >1.5 grams between the 1st and the 2nd dispensation; 4) Patients with MZ dosage >2.5 grams between the 1st and the 2nd dispensation. Each sub-group was stratified by age: ≤65 and >65, separately. We estimated adherence to MZ monthly, through the Medication Possession Ratio and computed adherence trajectories with a 3 step-procedure: 1) computation of 24 statistical measures; 2) factor analysis; 3) cluster analysis. We performed two sensitivity analyses: 1) Patients >65 years old with UC ICD-9 code, 2) Patients ≤65 years old with the UC exemption code. Results The sub-groups 1, 2, 3 and 4 included 47.750, 34.037, 29.730 and 26.165 MZ users, respectively. In all the sub-groups and stratification by age, 3 clusters of adherence were identified: high, medium low and low. The high adherence trajectory showed a mean adherence over 40% in the FUP, while patients in the low and medium low trajectories discontinued MZ within 5 and 15 months, respectively. The first and second sensitivity analysis included 409 and 1514 patients, respectively. Two clusters were identified in both analyses: high, around 80%, and moderate, up to 30% at the end of FUP. No MZ discontinuation was observed in the sensitivity analyses on ascertained UC patients. Conclusion In the main analyses, two out of three trajectories were characterized by MZ discontinuation, while in the trajectories calculated for the patients with UC codes, no MZ use interruption was detected. This finding could help the identification of true UC patients in the overall population of MZ users.

scholarly journals The influence of urban form and socio-demographics on active transport: A 40-neighborhoods study in Chengdu, China

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
ChengHe Guan ◽  
Ann Forsyth
Keyword(s):  
Active Transport ◽  
Urban Form ◽  
Multilevel Models ◽  
Personal Characteristics ◽  
Urban Environments ◽  
Sensitivity Analyses ◽  
Individual Level ◽  
Planning And Design ◽  
Intersection Density ◽  
Planning Culture

In China, a centralized planning culture has created similar neighborhoods across the country. Using a survey of 1,048 individuals conducted in 2016 in Chengdu—located in a carefully conceptualized typology of neighborhood forms—we analyzed the associations between individual and neighborhood characteristics and active or nonmotorized transport behavior. Using several multiple logistic and multilevel models, we show how neighborhoods were categorized and how the number of categories or neighborhood types affected the magnitude of the associations with active transport but not the direction. People taking non-work trips were more likely to use active compared with motorized modes in all neighborhood types. Neighborhood type was significant in models but so too were many other individual-level variables and infrastructural and locational features such as bike lanes and location near the river. Of the 3-D physical environment variables, floor area ratio (a proxy for density) was only significant in one model for nonwork trips. Intersection density and dissimilarity (land-use diversity) were only significant in a model for work trips. This study shows that to develop strong theories about the connections between active transport and environments, it is important to examine different physical and cultural contexts and perform sensitivity analyses. Research in different parts of China can help provide a more substantial base for evidence-informed policymaking. Planning and design recommendations were made related to active transport need to consider how neighborhoods, built environments, and personal characteristics interact in different kinds of urban environments.

Identification and Extrapolation of Causal Effects with Instrumental Variables

2018 ◽  
Vol 10 (1) ◽  
pp. 577-613 ◽  
Author(s):  
Magne Mogstad ◽  
Alexander Torgovitsky
Keyword(s):  
Instrumental Variables ◽  
Policy Evaluation ◽  
General Framework ◽  
Unobserved Heterogeneity ◽  
Causal Effect ◽  
Partial Identification ◽  
Causal Effects ◽  
Average Causal Effect ◽  
Special Cases ◽  
Selection On Unobservables

Instrumental variables (IV) are widely used in economics to address selection on unobservables. Standard IV methods produce estimates of causal effects that are specific to individuals whose behavior can be manipulated by the instrument at hand. In many cases, these individuals are not the same as those who would be induced to treatment by an intervention or policy of interest to the researcher. The average causal effect for the two groups can differ significantly if the effect of the treatment varies systematically with unobserved factors that are correlated with treatment choice. We review the implications of this type of unobserved heterogeneity for the interpretation of standard IV methods and for their relevance to policy evaluation. We argue that making inferences about policy-relevant parameters typically requires extrapolating from the individuals affected by the instrument to the individuals who would be induced to treatment by the policy under consideration. We discuss a variety of alternatives to standard IV methods that can be used to rigorously perform this extrapolation. We show that many of these approaches can be nested as special cases of a general framework that embraces the possibility of partial identification.

Scanning Tunneling Microscopy of Amorphous Carbon Films

1990 ◽  
Vol 48 (1) ◽  
pp. 318-319
Author(s):  
Mircea Fotino ◽  
D.C. Parks
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Amorphous Carbon ◽  
Carbon Films ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Amorphous Carbon Films ◽  
Image Optimization ◽  
Step Procedure ◽  
Stm Images

In the last few years scanning tunneling microscopy (STM) has made it possible and easily accessible to visualize surfaces of conducting specimens at the atomic scale. Such performance allows the detailed characterization of surface morphology in an increasing spectrum of applications in a wide variety of fields. Because the basic imaging process in STM differs fundamentally from its equivalent in other well-established microscopies, good understanding of the imaging mechanism in STM enables one to grasp the correct information content in STM images. It thus appears appropriate to explore by STM the structure of amorphous carbon films because they are used in many applications, in particular in the investigation of delicate biological specimens that may be altered through the preparation procedures.All STM images in the present study were obtained with the commercial instrument Nanoscope II (Digital Instruments, Inc., Santa Barbara, California). Since the importance of the scanning tip for image optimization and artifact reduction cannot be sufficiently emphasized, as stressed by early analyses of STM image formation, great attention has been directed toward adopting the most satisfactory tip geometry. The tips used here consisted either of mechanically sheared Pt/Ir wire (90:10, 0.010" diameter) or of etched W wire (0.030" diameter). The latter were eventually preferred after a two-step procedure for etching in NaOH was found to produce routinely tips with one or more short whiskers that are essentially rigid, uniform and sharp (Fig. 1) . Under these circumstances, atomic-resolution images of cleaved highly-ordered pyro-lytic graphite (HOPG) were reproducibly and readily attained as a standard criterion for easily recognizable and satisfactory performance (Fig. 2).

Procedure for Maximizing Phonological Information from Single-Word Responses

1984 ◽  
Vol 15 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Harriet B. Klein
Keyword(s):  
Phonological Information ◽  
Single Word ◽  
Preliminary Assessment ◽  
Target Attainment ◽  
Phonological Processes ◽  
Step Procedure ◽  
Yield Information ◽  
Assessment Measure ◽  
Busy Clinician ◽  
Planning Intervention

Formal articulation test responses are often used by the busy clinician as a basis for planning intervention goals. This article describes a 6-step procedure for using efficiently the single-word responses elicited with an articulation test. This procedure involves the assessment of all consonants within a word rather than only test-target consonants. Responses are organized within a Model and Replica chart to yield information about an individual's (a) articulation ability, (b) frequency of target attainment, substitutions, and deletions, (c) variability in production, and (d) phonological processes. This procedure is recommended as a preliminary assessment measure. It is advised that more detailed analysis of continuous speech be undertaken in conjunction with early treatment sessions.

Influence of General and Crystallized Intelligence on Vocabulary Test Performance

2002 ◽  
Vol 18 (1) ◽  
pp. 78-84 ◽  
Author(s):  
Eva Ullstadius ◽  
Jan-Eric Gustafsson ◽  
Berit Carlstedt
Keyword(s):  
Hierarchical Model ◽  
Test Performance ◽  
Verbal Ability ◽  
Testing Procedure ◽  
Intellectual Ability ◽  
Analysis Of Covariance ◽  
Categorical Variables ◽  
Vocabulary Test ◽  
Crystallized Intelligence ◽  
General Ability

Summary: Vocabulary tests, part of most test batteries of general intellectual ability, measure both verbal and general ability. Newly developed techniques for confirmatory factor analysis of dichotomous variables make it possible to analyze the influence of different abilities on the performance on each item. In the testing procedure of the Computerized Swedish Enlistment test battery, eight different subtests of a new vocabulary test were given randomly to subsamples of a representative sample of 18-year-old male conscripts (N = 9001). Three central dimensions of a hierarchical model of intellectual abilities, general (G), verbal (Gc'), and spatial ability (Gv') were estimated under different assumptions of the nature of the data. In addition to an ordinary analysis of covariance matrices, assuming linearity of relations, the item variables were treated as categorical variables in the Mplus program. All eight subtests fit the hierarchical model, and the items were found to load about equally on G and Gc'. The results also indicate that if nonlinearity is not taken into account, the G loadings for the easy items are underestimated. These items, moreover, appear to be better measures of G than the difficult ones. The practical utility of the outcome for item selection and the theoretical implications for the question of the origin of verbal ability are discussed.

Modeling Intraindividual Variability in Three-Level Multilevel Models

Methodology ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Steffen Nestler ◽  
Katharina Geukes ◽  
Mitja D. Back
Keyword(s):  
Multilevel Model ◽  
Multilevel Models ◽  
Mixed Effects ◽  
Repeated Measurements ◽  
Scale Model ◽  
Suggested Approach ◽  
Psychological Study ◽  
Level Data ◽  
Ecological Momentary ◽  
Momentary Assessment

Abstract. The mixed-effects location scale model is an extension of a multilevel model for longitudinal data. It allows covariates to affect both the within-subject variance and the between-subject variance (i.e., the intercept variance) beyond their influence on the means. Typically, the model is applied to two-level data (e.g., the repeated measurements of persons), although researchers are often faced with three-level data (e.g., the repeated measurements of persons within specific situations). Here, we describe an extension of the two-level mixed-effects location scale model to such three-level data. Furthermore, we show how the suggested model can be estimated with Bayesian software, and we present the results of a small simulation study that was conducted to investigate the statistical properties of the suggested approach. Finally, we illustrate the approach by presenting an example from a psychological study that employed ecological momentary assessment.

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