Causal mediator 2026-10-25
A random variable on a proposed causal pathway from a cause to an outcome. A causal mediator transmits part of a causal effect; statistical association with the cause and outcome alone does not establish that role.
Elaboration model 2026-10-25
The elaboration model compares a pooled statistical association with the associations conditional on a third variable. Replication describes a similar pattern within the strata. Specification describes a relationship whose size or direction varies between strata. Attenuation can suggest explanation by an antecedent confounder, or interpretation through an intervening causal mediator. These causal readings require justified temporal and causal assumptions; conditional tables alone do not identify the third variable's role.[ref]
The Practice of Social Research (13th edition) by Earl Babbie. Chapter 15, printed p. 448, Table 15-5: relationship patterns and antecedent/intervening test variables
Assess the patterns through conditional probabilities or comparable effect sizes. Different p-values also reflect different sample sizes and standard errors, so significant and nonsignificant results need not differ significantly.
Anxiety disorders centrally involve cognition, but describing them solely as disorders of cognition is too strong unless the term is defined so broadly that it loses explanatory value. Threat appraisal, attention, interpretation and memory can contribute to excessive fear and avoidance. Bodily arousal, learning history, action and the environment also matter. A useful account specifies how these processes interact and asks whether changing a proposed cognitive process changes anxiety, rather than simply observing that anxious people report anxious thoughts.
David M. Clark's cognitive model of panic illustrates the explanatory gain. Ordinary sensations such as a racing heart can be interpreted as evidence of imminent catastrophe. Fear increases arousal, which provides further sensations for threatening interpretation. The account distinguishes the bodily input from its meaning and explains why similar sensations need not produce the same fear in different circumstances. It also predicts that precautions and avoidance can prevent disconfirmation. The 1986 paper supplied a mechanistic model, not by itself proof that every panic episode requires a consciously articulated catastrophic thought.[ref]
A cognitive approach to panic by David M. Clark. Behaviour Research and Therapy 24, 461–470; catastrophic interpretation model, not a new clinical trial
The distinction between cognition and explicit verbal reasoning matters. A person may orient rapidly toward threat, experience an image or respond to a bodily sensation before they can describe a proposition. Absence of a reported sentence does not establish absence of information processing. Equally, a theory should not rescue itself from every negative finding by postulating an inaccessible belief. It must specify observable predictions and measures that can fail, including what would count as successful alteration of the proposed process.
Cross-sectional evidence is insufficient to establish direction. A threat interpretation could increase anxiety, anxiety could bias the interpretation, or a third factor could influence both. Questionnaires can also partly measure the same evaluative content on both sides of the association. Longitudinal prediction improves temporal ordering but leaves confounding possible. Experiments that manipulate interpretation or attention therefore offer a stronger test, especially when changes in the intended process are verified separately from changes in symptoms.
Andrew Mathews and Bundy Mackintosh reported five experiments inducing relatively threatening or benign interpretations of ambiguous material. Interpretative bias could be changed, but parallel effects on state anxiety depended on active processing of personally relevant meanings. This supports a causal contribution under specified conditions and shows that a changed task response need not automatically mean changed emotional experience. These experiments do not establish that an interpretation-training task is a complete treatment for a diagnosed anxiety disorder.[ref]
Induced emotional interpretation bias and anxiety by Andrew Mathews and Bundy Mackintosh. Journal of Abnormal Psychology 109, 602–615; five experiments, ambiguity training, active meaning generation and state anxiety
Colin MacLeod and colleagues manipulated selective attention using a modified dot-probe procedure. The location of a subsequent probe was used to train attention in different directions relative to emotional material, followed by a standardised stress task. Differences in emotional vulnerability support a contribution from attention rather than association alone. Transfer from a laboratory induction to enduring clinical change, however, remains an additional question. Learning a task contingency, altered expectancies and the reliability of the process measure all require consideration.[ref]
Selective attention and emotional vulnerability: assessing the causal basis of their association through the experimental manipulation of attentional bias by Colin MacLeod and others. Journal of Abnormal Psychology 111, 107–123; modified dot-probe training and responses to a standardised stress task
Clinical treatment comparisons provide complementary evidence. David M. Clark and colleagues compared cognitive therapy, applied relaxation and imipramine in panic disorder, with self-exposure homework shared across conditions. The findings supported cognitive therapy as a useful treatment. They do not make the comparison a pure test of thought change against an absence of learning or behavior: treatment packages differ in multiple ways, and a pharmacological treatment can also alter the sensations and experiences from which beliefs are formed.[ref]
A comparison of cognitive therapy, applied relaxation and imipramine in the treatment of panic disorder by David M. Clark and others. British Journal of Psychiatry 164, 759–769; treatment comparison, common self-exposure homework and follow-up
Safety behavior research further shows why a sharp cognition-versus-behavior division can mislead. Paul Salkovskis and colleagues found that changing precautions during exposure altered catastrophic beliefs and anxiety. The behavior may control which evidence is encountered and how success is explained. Conversely, a different explanation may make abandoning the behavior possible. These reciprocal effects favour a specified feedback system over treating observable action and mental representation as competing, self-contained causes.[ref]
An experimental investigation of the role of safety-seeking behaviours in the maintenance of panic disorder with agoraphobia by Paul Salkovskis and others. Behaviour Research and Therapy 37, 559–574; brief exposure manipulation and repeated behavioural test
Learning accounts also need not exclude cognition. An inhibitory learning approach proposes that exposure establishes alternative expectations rather than necessarily erasing the original threat association. Context-dependent retrieval can explain return of fear after apparently successful practice. Michelle G. Craske and colleagues developed a translational framework around this distinction. It offers a way to connect expectation, experience and later retrieval, while its clinical implementation requires direct evaluation rather than assuming that a learning rationale proves a particular protocol optimal.[ref]
Maximizing exposure therapy: An inhibitory learning approach by Michelle G. Craske and others. Behaviour Research and Therapy 58, 10–23; inhibitory-learning framework and illustrative strategies, not a component trial
The broader phrase 'anxiety disorders' also conceals heterogeneity. The feared consequence in social anxiety differs from the interpretation of bodily sensations in panic or persistent worry about many possible outcomes. A common information processing principle can coexist with disorder-relevant mechanisms. Actual danger and social adversity must be assessed: an expectation is not distorted simply because it concerns something distressing. Genetic, developmental and physiological influences can affect sensitivity to threat without fixing the meaning or outcome of every encounter.
Strong evidence for a particular cognitive mechanism would combine an experimental manipulation, a successful process check, subsequent change in fear and transfer to relevant everyday behavior. A factorial design could vary interpretation and a maintaining precaution separately, with matched contact and exposure opportunities. Repeated measurements should establish whether the cognitive change precedes the outcome. Treatment randomisation identifies the package effect, but mediation requires additional assumptions because the mediator itself has not necessarily been randomised.
Evidence against an exclusive account would include effective treatment without the predicted process change, or a precise null effect on anxiety after a successful, sufficiently strong manipulation of that process. Such a result might constrain the population or context in which the mechanism matters rather than rule out all cognitive contributions. Measurement sensitivity and alternative pathways must be considered without making the theory unfalsifiable.
The defensible conclusion is that cognition contributes materially to the persistence and modification of anxiety, with experimental evidence beyond introspective report. It is less defensible to claim that all anxiety disorders are caused only by consciously held false beliefs, or that the success of cognitive therapy establishes that exclusivity. Mechanistic precision and evidence about causal interaction are more informative than choosing between cognition, the body and behavior as if only one could matter.
A psychological treatment has a specific effect only relative to a clearly defined alternative explanation. Benefit beyond waiting is different from benefit beyond credible therapeutic contact, and both differ from evidence that a named technique works through its proposed mechanism. No single research design establishes all three. A persuasive programme combines controlled clinical comparisons with component and process experiments, while keeping patient-relevant outcomes central.
An uncontrolled before-and-after study cannot isolate a treatment effect. People may enter care when symptoms are unusually severe, creating regression toward their longer-term level; difficulties can improve naturally; expectations, concurrent care and repeated assessment can also change outcomes. A waiting-list randomised trial controls some time-related explanations but adds unequal expectations and contact. It can establish benefit from being offered the treatment package compared with waiting under those conditions, without identifying which ingredient produced the difference.
For specificity beyond nonspecific therapy effects, use a randomised comparison with a credible active intervention. Match time, attention, therapist competence and assessment opportunities as far as the question permits. Measure credibility and expected benefit rather than assuming equivalence from similar session counts. Keep relevant usual care available in both arms. Allocation concealment prevents recruitment decisions from anticipating the next assignment, while blinded independent outcome assessment reduces a different source of bias after allocation. Therapists and patients usually cannot be fully blinded to psychological procedures.
Daniel Freeman and colleagues' Feeling Safe trial illustrates this stronger package comparison. Patients with persistent persecutory delusions received the programme or befriending delivered by the same therapists, alongside usual care. At six months, the primary continuous conviction measure favoured Feeling Safe. This supports an effect beyond the particular befriending comparator, but does not establish that each module is necessary or that the whole benefit travelled through one nominated mediator.[ref]
Comparison of a theoretically driven cognitive therapy (the Feeling Safe Programme) with befriending for the treatment of persistent persecutory delusions: a parallel, single-blind, randomised controlled trial by Daniel Freeman and others. Lancet Psychiatry 8, 696–707; 130 patients, same-therapist befriending, six-month continuous conviction and categorical recovery distinction
The comparator should be interpreted fairly. A weak or implausible control can exaggerate apparent specificity, while an active comparator may itself change the proposed mechanism. If befriending improves social confidence, it is not a biologically inert placebo. A null result may mean two useful treatments have similar effects, both are ineffective, or the study is too imprecise. Failure of a superiority test does not demonstrate equivalence; an equivalence or noninferiority question requires prespecified clinically justified margins and appropriate precision.
A dismantling trial varies a specified component while keeping the surrounding treatment adequate and similar. For example, compare the same exposure programme with and without a safety behavior intervention. This estimates a conditional contribution: absence of an additional benefit does not imply that the component is useless in every context, because another part may produce similar learning. A factorial design can independently vary an action and its explanatory rationale, estimating their effects and interaction when the study has adequate power.
The early panic safety behavior experiment provides both an example and a caution. Greater change after brief exposure with precautions reduced supports the combined manipulation. Yet behavioral instructions and the explanation of the exercise were not fully separated. The appropriate next test would vary those elements independently and check actual behavior and expectancy change. Simply renaming the conditions 'cognitive' and 'behavioral' would not remove the confounding.[ref]
An experimental investigation of the role of safety-seeking behaviours in the maintenance of panic disorder with agoraphobia by Paul Salkovskis and others. Behaviour Research and Therapy 37, 559–574; brief exposure manipulation and repeated behavioural test
A mechanistic experiment can provide more direct leverage than a full treatment comparison. Colin MacLeod and colleagues trained attentional bias using a modified dot-probe task and tested later responses to stress. This asked whether experimentally changing information processing altered emotional vulnerability. It remains necessary to establish that the manipulation engaged the intended process rather than only a task-specific strategy, and that any effect transfers to the clinical phenomenon of interest. Laboratory emotional vulnerability is not itself diagnostic remission.[ref]
Selective attention and emotional vulnerability: assessing the causal basis of their association through the experimental manipulation of attentional bias by Colin MacLeod and others. Journal of Abnormal Psychology 111, 107–123; modified dot-probe training and responses to a standardised stress task
Likewise, Daniel Freeman and colleagues used virtual social environments to compare exposure against threat testing with safety behavior reduction. Both groups encountered graded situations, making the content of learning more directly investigable than in a therapy-versus-waiting comparison. The combined manipulation and brief follow-up constrain the mechanism claim. A useful manipulation check, an independent behavioral outcome and later transfer assessment strengthen the design more than a treatment label does.[ref]
Virtual reality in the treatment of persecutory delusions: randomised controlled experimental study testing how to reduce delusional conviction by Daniel Freeman and others. British Journal of Psychiatry 209, 62–67; 30 participants, graded social environments, safety reduction versus exposure and real-world assessment
Mediation analysis is informative but insufficient on its own. Randomising treatment identifies the total effect of assignment under the trial's assumptions; it does not automatically randomise the mediator. Symptom improvement could change reported beliefs, or an unmeasured process could influence both the belief score and the outcome. Measure the proposed mediator before the downstream outcome, assess competing pathways and perform sensitivity analyses. Replication using a different way to alter the same process can provide converging evidence; stronger identification may require experimental manipulation of that process itself.
Clinical trials also need suitable sampling, prespecified outcomes, adequate power, intention-to-treat analysis and transparent missing data handling. Outcomes should include functioning and possible deterioration, with follow-up long enough to distinguish transient reassurance from durable benefit. Treatment fidelity and competence must be assessed in both arms. Therapist allegiance, clustering of patients within therapists and differential dropout can affect interpretation. Statistical significance alone does not establish a meaningful improvement, especially when many outcomes or subgroup comparisons are explored.
Pragmatic implementation trials answer a complementary question: does the intervention add benefit in ordinary care, at acceptable cost and burden? Jaime Delgadillo and colleagues' therapist-cluster trial tested an automated feedback system linked to supervisory review within routine services. Its comparison isolates the added feedback arrangement more closely than an observational association between high-performing services and monitoring. It still tests a specified package of information and response, rather than an abstract effect of measurement divorced from clinical action.[ref]
Feedback-informed treatment versus usual psychological treatment for depression and anxiety: a multisite, open-label, cluster randomised controlled trial by Jaime Delgadillo and others. Lancet Psychiatry 5, 564–572; 77 participating therapists, 2233 patients, cluster allocation and not-on-track outcomes
The strongest conclusion consequently states its level of specificity. A well-conducted active control trial can establish an incremental treatment-package effect. A dismantling or factorial trial can identify a component's contribution within a defined context. An experimental process manipulation, supported by temporally ordered measurements and converging clinical evidence, can constrain the mechanism. Keeping these claims separate prevents a successful therapy from being treated as proof of its entire theory, while preserving the practical importance of improvements patients actually experience.
Recent innovations offered plausible routes to better outcomes for delusions by replacing a broad, undifferentiated treatment target with specific maintaining processes. Persistent persecutory beliefs may be supported by worry, poor sleep, felt vulnerability, low confidence, reasoning inflexibility and safety behaviors. Changing one of these may create opportunities for a person to reconsider threat without demanding immediate agreement that their belief is wrong. The promise is mechanistic and practical; it does not imply that all delusions share one cause or that every plausible target will improve clinical outcomes.
A contributory-causal approach begins by identifying a potentially modifiable process, experimentally changing it and examining consequences for the clinical problem. Worry is an example: repeated anticipation of danger can generate threatening explanations and keep them mentally available. In the Worry Intervention Trial, Daniel Freeman and colleagues randomised 150 patients with persistent persecutory delusions to six sessions targeting worry alongside standard care, or standard care alone. Worry and delusion outcomes improved, with gains followed to 24 weeks. Because therapist contact was not matched, the result supports the added intervention package more securely than an exclusively worry-mediated effect.[ref]
Effects of cognitive behaviour therapy for worry on persecutory delusions in patients with psychosis (WIT): a parallel, single-blind, randomised controlled trial with a mediation analysis by Daniel Freeman and others. Lancet Psychiatry 2, 305–313; 150 patients, six worry sessions plus usual care versus usual care, eight-/24-week outcomes
Sleep offers a different entry point that may be more acceptable than directly debating a threat belief. The OASIS trial randomised 3755 university students with insomnia to digital CBT for sleep or usual practice. It produced a large sleep benefit and smaller changes in paranoia and hallucinatory experiences. This supports testing sleep as a contributory process, while the nonclinical student sample and usual-practice comparator prevent direct inference that the same intervention treats persistent delusions in patients with psychosis.[ref]
The effects of improving sleep on mental health (OASIS): a randomised controlled trial with mediation analysis by Daniel Freeman and others. Lancet Psychiatry 4, 749–758; 3755 university students with insomnia, digital CBT versus usual practice and population limits
The Feeling Safe Programme combined individually selected modules addressing relevant maintaining factors. Its 2021 trial allocated 130 patients with persistent persecutory delusions to Feeling Safe or same-therapist befriending, with usual care continuing. The six-month adjusted difference in delusional conviction favoured Feeling Safe by about 10.7 points on a 0–100 scale. A categorical recovery comparison was less precise and did not reach conventional significance. The positive continuous primary outcome therefore should not be restated as a definitively superior recovery rate.[ref]
Comparison of a theoretically driven cognitive therapy (the Feeling Safe Programme) with befriending for the treatment of persistent persecutory delusions: a parallel, single-blind, randomised controlled trial by Daniel Freeman and others. Lancet Psychiatry 8, 696–707; 130 patients, same-therapist befriending, six-month continuous conviction and categorical recovery distinction
Reasoning interventions aim to increase flexibility and slow hasty acceptance of threatening explanations. Philippa Garety and colleagues' SlowMo combined eight face-to-face sessions, digital material and a mobile application. In the 361-person analysis, the primary total paranoia score at 24 weeks did not show a statistically significant advantage over usual care, although several secondary and earlier outcomes favoured the intervention. There was no significant effect on jumping to conclusions. This mixed pattern is particularly important: an engaging, mechanistically informed treatment can show promising signals without meeting its prespecified primary test.[ref]
Effects of SlowMo, a Blended Digital Therapy Targeting Reasoning, on Paranoia Among People With Psychosis: A Randomized Clinical Trial by Philippa Garety and others. JAMA Psychiatry 78, 714–725; 361 in analysis, prespecified 24-week GPTS total endpoint and secondary outcomes
These approaches could improve outcomes for several reasons. Targeting common difficulties such as insomnia or worry can give treatment an understandable starting point. Personalised modules can concentrate time on processes actually present instead of requiring every patient to complete the same sequence. Concrete experiments may provide more persuasive evidence than verbal reassurance. Digital support can make an exercise accessible between appointments, while carefully designed measures can show whether the nominated process changed before the belief or distress changed.
However, a target can be associated with delusions without causing them. Poor sleep and worry may partly reflect a common adversity, or lessen when general distress improves. An intervention intended for one process can alter several others, making a statistical mediator an uncertain guide to the active ingredient. Even when a factor contributes causally, changing it may produce only modest benefit because other maintaining processes remain. Necessary theoretical precision includes specifying who has the target, how much it must change and which outcome should follow.
Outcome choice can make an innovation appear more or less successful. Conviction, preoccupation, distress, activity, quality of life and diagnostic status are related but distinct. Greater doubt about a threatening explanation may be valuable without elimination of the belief; conversely, a questionnaire change need not restore work or social participation. The difference between SlowMo's primary and secondary findings illustrates why the endpoint and assessment time should be specified in advance. Multiple favourable secondary results cannot simply replace an unsuccessful primary test.
Clinical heterogeneity also matters. A treatment developed for persistent persecutory delusions is not automatically established for every delusional theme, acute state or diagnostic group. Language requirements, willingness to attend research therapy and referral patterns select who enters a trial. Comorbid depression, cognitive difficulties, substance use or continuing victimisation may alter the usefulness of a module. An unusual belief should be assessed in its cultural and social context; a psychological account must not assume that all reported threats are unreal.
Innovations can fail at implementation even when the trial mechanism is sound. Skilled research therapists, close supervision and protected time may be unavailable in routine services. A mobile application can increase opportunity for practice but also introduce access, privacy or comprehension barriers. Adding modules can increase burden, dilute effective content or delay the experiment that matters most. Patients may prefer a different target from the one selected by a questionnaire. Acceptability, fidelity, reach and cost therefore need direct measurement alongside symptom outcomes.
A strong next study would compare an adapted innovation with a credible active treatment in several services, with adequate power and blinded assessment. Prespecify primary conviction or distress outcomes, patient-prioritised functioning and longer-term maintenance. Measure candidate mechanisms repeatedly, recording which modules are actually received; module choice in a tailored treatment is not random and cannot itself identify the best component. A complementary factorial or sequentially randomised experiment could test specific additions while preserving adequate care for all participants.
By May 2022, the most convincing advance was the shift toward testable mechanisms and more rigorous, symptom-focused clinical comparisons. Worry, sleep, flexible reasoning and personalised threat-learning approaches offered reasons for optimism, with some positive clinical results and important null findings. Better outcomes would depend on genuine target engagement, adequate comparisons, generalisation and feasible delivery, rather than novelty, a digital format or a plausible causal diagram alone.
The association remains positive within each income group, although its estimated size is smaller in the higher-income groups. The two extreme trust categories give the following conditional vaccination percentages and differences:
| Annual household income | Lowest trust | Highest trust | Difference in percentage points |
|---|---|---|---|
| Below £20,000 | 36.36% | 89.60% | 53.24 |
| £20,000–£40,000 | 50.00% | 93.10% | 43.10 |
| £40,000 and above | 66.67% | 91.14% | 24.47 |
In the lowest-income group, the intervening percentages are 42.86%, 44.12% and 82.54%, so the increase is monotone. Its Pearson chi-squared statistic is approximately 62.520 on four statistical degrees of freedom, with the printed asymptotic . Cramér's V is approximately 0.441, Goodman and Kruskal's gamma is approximately 0.626 and the column-dependent Somers' D is approximately 0.259. The column-dependent Goodman and Kruskal's lambda is approximately 0.158: trust improves the modal prediction more here than in the pooled table.
In the middle-income group, the intervening vaccination percentages are 61.54%, 81.82% and 92.04%. The printed Pearson chi-squared statistic is approximately 24.033 on four statistical degrees of freedom, with asymptotic . Cramér's V is approximately 0.298, Goodman and Kruskal's gamma approximately 0.454 and column-dependent Somers' D approximately 0.100. Column-dependent Goodman and Kruskal's lambda is zero: vaccinated respondents are the majority in every row, so the modal prediction never changes. A zero lambda does not mean independence.
In the highest-income group, the intermediate vaccination percentages are 71.43%, 76.92% and 94.55%; the final category falls slightly to 91.14%. Thus the observed pattern is broadly positive rather than strictly monotone. The printed Pearson chi-squared statistic is approximately 8.199 on four statistical degrees of freedom, with asymptotic . It does not reject independence at 5%. The corresponding Cramér's V is approximately 0.229, Goodman and Kruskal's gamma approximately 0.281 and column-dependent Somers' D approximately 0.058. The column-dependent Goodman and Kruskal's lambda is again zero.
Small counts limit the asymptotic tests, especially in the middle- and highest-income tables. Their minimum expected counts are approximately 0.644 and 0.306, with respectively 30% and 40% of cells below five. The lowest-income table has one expected count below five, with minimum approximately 3.315. These diagnostics concern expected counts under independence, not just the observed row sizes.
The supplied counts are sufficient to make an exact conditional Pearson test for a binary contingency table, without needing individual records or assuming a chi-squared distribution approximation. Conditioning on the row totals and total unvaccinated count removes the common unknown binomial probability. For each admissible table, sum its multivariate hypergeometric distribution probability when its Pearson chi-squared statistic is at least the observed one. Complete enumeration gives:
| Income group | Enumerated tables | Exact conditional p-value |
|---|---|---|
| Lowest | 507150 | |
| Middle | 22379 | |
| Highest | 2585 |
These are new exact conditional calculations, rather than the paper's printed asymptotic p-values. They confirm evidence of association in the first two groups and nonrejection at 5% in the third, while showing the numerical effect of sparse cells. The tail is ordered by the Pearson chi-squared statistic; an exact test with a different ordering need not have the same p-value. Fixed-margin Monte Carlo tests approximate this same Pearson-ordered tail when enumeration is impractical.[ref]
Pearson's Chi-squared Test for Count Data in the R documentation. Details: fixed-marginal simulation for contingency-table Pearson tests
The original count-based figure below includes pointwise approximate 95% Wilson intervals. The very wide intervals for sparsely populated trust categories make the uncertainty visible; they are not simultaneous intervals or a formal test of differences between income groups.
In the elaboration model, the positive direction is replicated after conditioning on income: income does not fully explain away the observed trust–vaccination relationship. The decreasing estimated contrasts and ordered coefficients suggest possible specification by income, or effect modification on an explicitly chosen scale. They do not establish it. Different p-values can arise from different sample sizes and standard errors; significant and nonsignificant results need not differ significantly. A formal statistical interaction test or a confidence interval for differences between comparable contrasts would address that question.[ref]
The Practice of Social Research (13th edition) by Earl Babbie. Chapter 15, Table 15-5: replication, specification and the causal ordering needed for explanation or interpretation
Nor do these conditional tables prove that income is a causal confounder or causal mediator. Those labels require assumptions about causal order, relevant confounding and how variables were measured. This is an observational study of recorded vaccination status, not a randomized change in trust or a test of vaccine effectiveness.
Conditioning on marital status produces five contingency tables. In each, compare the conditional row percentages. The following differences are the sample proportion with some bad experiences minus the sample proportion without them, in percentage points; negative very-safe differences mean fewer respondents feeling very safe in the former group.
| Marital-status stratum | Difference: very safe | Difference: unsafe | Reported Pearson's chi-squared test p-value | Cramér's V | Goodman and Kruskal's gamma |
|---|---|---|---|---|---|
| Single | |||||
| Married | |||||
| Living with a partner | (inconsistent; see below) | ||||
| Divorced | |||||
| Widowed |
The p-values test independence within the respective strata; the magnitudes and directions come from the conditional percentages and association measures. Differences in the table are calculated from the counts before rounding.
Among single respondents, the very-safe sample proportion changes from to , while the unsafe sample proportion changes from to . The direction resembles the weak pooled pattern, but supplies little evidence against independence in this stratum. This is not evidence that the population association is exactly zero.
Among married respondents, the very-safe sample proportion changes from to and the fairly-safe sample proportion rises from to . Unsafe remains almost unchanged, versus . Thus the within-stratum association again chiefly shifts very safe toward fairly safe. Its is below the significance level, while still indicates a small association.
For respondents living with a partner, very safe changes from to , fairly safe from to , and unsafe from to . The very-safe difference is larger than in the married stratum. The printed p-value would be just below the conventional significance level. However, this particular output is internally inconsistent: recalculating Pearson's chi-squared test from its six displayed counts gives , , and . The reported agrees with the counts, whereas the printed would itself imply for two statistical degrees of freedom, rather than the printed . Using the displayed counts, this stratum does not reject independence at . The source PDF itself contains these incompatible figures; this is not resolved by rounding.
Among divorced respondents, very safe changes from to , but unsafe also decreases, from to , as fairly safe increases from to . This is a redistribution toward the middle category, not a simple shift toward greater unsafety. The near-zero gamma, , reflects the lack of a consistent ordinal direction, while can still register distributional differences without a direction. The p-value does not reject independence.
Among widowed respondents, very safe changes from to , and unsafe from to . The ordinal association is positive on the chosen ordering, with gamma . Its lack of conventional statistical significance, , does not imply a smaller estimated association than in the married group: the widowed stratum has only complete observations, versus in the married stratum, and therefore less precision. All five tables have sufficiently large expected counts for the reported approximations; even the smallest expected count is about .
The plot uses large-sample Wald confidence intervals for the difference of independent sample proportions within each stratum. They concern the individual category contrasts, whereas the tabulated Pearson's chi-squared tests compare the full three-category distributions. The intervals are unadjusted for multiple hypothesis testing; the pooled row reuses the stratum observations, so it is not a sixth independent sample.
In the elaboration model, the persistence of a generally weak positive ordinal pattern within four strata is closer to partial replication than to a complete explanation of the pooled association by marital status. The differences in estimated patterns suggest possible specification: the divorced group's shift toward the middle category differs from the widowed group's shift toward unsafe. They do not by themselves establish population effect modification. In particular, significant and nonsignificant results need not differ significantly; compare the effects using an interaction contrast or a fitted model with the appropriate interaction terms, rather than comparing their separate p-values.[ref]
The Difference Between Significant and Not Significant is not Itself Statistically Significant by Andrew Gelman and Hal Stern. Printed p. 328, Introduction: comparing significance labels does not test the difference between estimates
One additional omnibus check can be derived from the supplied tables without assuming a common effect. Recalculating the five statistics from the counts, including the corrected living-with-partner statistic, the joint conditional independence test for stratified contingency tables givesUnder independent-stratum sampling this tests independence within every stratum jointly; it does not test whether the association is homogeneous across strata. It does not reject at , but this alone does not establish that stratification removed the population association: its ten-degree-of-freedom alternative is less focused than the pooled two-degree-of-freedom test, and nonrejection is not proof of equality.
The elaboration model also distinguishes an antecedent confounder from an intervening causal mediator. These cross-sectional tables do not establish the relevant time ordering or identify either role for marital status. Five separate stratum tests further require caution about multiple hypothesis testing: for example a Bonferroni correction at familywise would use per test, below all five individual p-values. That caution changes the interpretation of selected significance labels, not the observed conditional percentages.
The estimated patterns vary across strata, but the tables neither establish a population interaction nor prove that marital status explains away the association.

