Table 3.
Probability ratios for an original @CDC_AMD tweet being retweeted in a negative binomial regression model that includes both the variable for photo or video attachment and the content variable (Model B), and one without content variable (Model C); in a hurdle model that includes both the variable for photo or video attachment and the content variable (Model D) and one without the content variable (Model E).
| Explanatory variables of each model | Probability ratio (95% CI) | P value | ||
| Model B (negative binomial model) |
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Contained a photo or video | 1.406 (1.114-1.775) | .004 | |
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Content |
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|
Referred to the CDCa AMDb website | Reference | - |
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Publication in content | 0.874 (0.638-1.197) | .40 |
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Webinar in content | 1.081 (0.643-1.832) | .77 |
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Bioinformatics in content | 1.381 (0.834-2.311) | .21 |
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Scientist in content | 1.066 (0.544-2.120) | .85 |
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Miscellaneous content | 1.355 (1.035-1.778) | .03 |
| Model C (negative binomial model) |
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Contained a photo or video | 1.374 (1.129-1.674) | .002 | |
| Model D (hurdle model)c |
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Zero or positive (logistic): Contained a photo or video | 1.643 (1.137-2.374) | .008 | |
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Zero or positive (logistic): Content |
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|
Referred to the CDC AMD website | Reference | - |
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Publication in content | 1.179 (0.740-1.878) | .49 |
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Webinar in content | 1.329 (0.579-3.046) | .50 |
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Bioinformatics in content | 2.260 (0.965-5.296) | .06 |
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Scientist in content | 1.685 (0.557-5.097) | .36 |
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Miscellaneous content | 1.150 (0.743-1.782) | .53 |
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Positive count (negative binomial): Contained a photo or video | 1.257 (0.917-1.724) | .16 | |
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Positive count (negative binomial): Content |
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|
Referred to the CDC AMD website | Reference | - |
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Publication in content | 0.652 (0.417-1.022) | .06 |
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Webinar in content | 0.929 (0.463-1.867) | .84 |
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Bioinformatics in content | 0.999 (0.511-1.950) | >.99 |
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Scientist in content | 0.774 (0.314-1.907) | .58 |
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Miscellaneous content | 1.501 (1.046-2.153) | .03 |
| Model E (Hurdle model)c |
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Zero or positive (logistic): Contained a photo or video | 1.442 (1.059-1.963) | .02 | |
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Positive count (negative binomial): Contained a photo or video | 1.344 (1.021-1.770) | .04 | |
aCDC: Centers for Disease Control and Prevention.
bAMD: advanced molecular detection.
cHurdle models include two model components: a logistic model and a negative binomial model.