| Abstract: | Survival models assume that fates of individuals are independent, yet the robustness of this assumption has been poorly quantified. We examine how empirically derived estimates of the variance of survival rates are affected by dependency in survival probability among individuals. We used Monte Carlo simulations to generate known amounts of dependency among pairs of individuals and analyzed these data with Kaplan-Meier and Cormack-Jolly-Seber models. Dependency significantly increased these empirical variances as compared to theoretically derived estimates of variance from the same populations. Using resighting data from 168 pairs of black brant, we used a resampling procedure and program RELEASE to estimate empirical and mean theoretical variances. We estimated that the relationship between paired individuals caused the empirical variance of the survival rate to be 155% larger than the empirical variance for unpaired individuals. Monte Carlo simulations and use of this resampling strategy can provide investigators with information on how robust their data are to this common assumption of independent survival probabilities. |
| Genre: | Article |
| ProdID: | 70007049 |
| Citation Author: | Schmutz, Joel A.; Ward, David H.; Sedinger, James S.; Rexstad, Eric A. |
| Citation Contributing Office: | Alaska Biological Science Center |
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| Citation End Page: | 681 |
| Citation Issue: | 5/6 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Applied Statistics |
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| Citation Number Of Pages: | 9 |
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| Citation Phsyical Description: | 9 p. |
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| Citation Public Comments: | None |
| Citation Publisher: | Taylor & Francis |
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| Citation Search Results Text: | Survival estimation and the effects of dependency among animals; 1995; Article; Journal; Journal of Applied Statistics; Schmutz, Joel A.; Ward, David H.; Sedinger, James S.; Rexstad, Eric A. |
| Citation Start Page: | 673 |
| Citation Volume: | 22 |
| Citation Year: | 1995 |
| Type: | citation/reference |
| Text: | Survival estimation and the effects of dependency among animals; 1995; Article; Journal; Journal of Applied Statistics; Schmutz, Joel A.; Ward, David H.; Sedinger, James S.; Rexstad, Eric A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1080/02664769524531 |
| Date Other: | Sun, 1 Jan 2012 14:12 -0600 |
| Publisher: | Taylor & Francis |
