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Results from COVID Stress Scale measurement invariance tests across times 1 and 2.

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Results from COVID Stress Scale item response models with parameter constraints across times 1 and 2 supported by DIF tests.

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Tests of discriminant validity: Comparison of the CSS-PL correlations with current anxiety and depression.

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Tests of discriminant validity: Comparison of the mean correlations for distress measures versus correlation with general xenophobia.

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Scree plots for COVID Stress Scales item factor analyses in the Polish and Dutch samples.

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Fig 2 -

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Sample characteristics of the total sample at T1 and T22 and as a function of attrition rate between T1 and T2.

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Model fit for exploratory structural equation models across Polish and Dutch samples.

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Results from COVID Stress Scales measurement invariance tests across Polish and Dutch samples.

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Results from COVID Stress Scales item response models with parameter constraints across Polish and Dutch samples supported by measurement invariance tests.