A gamma prior distribution which can be shifted.
shifted_gamma(shape = 1, scale = 1, shift = 0, autoscale = TRUE)
| shape, scale | Sets the shape and scale parameters of the Gamma prior. |
|---|---|
| shift | The Gamma prior can be shifted to allow for positive support. |
| autoscale | Same as in |
A named list to be parsed internally by epim.
rstanarm provides a set of distributions
(see priors) which can be used for the priors
on regression parameters. Intuitively, non-pharmaceutical interventions are
unlikely to a-priori cause a large increase in the reproduction number.
A shifted gamma prior can
be used to model this idea, and has been used in
Flaxman et al. (2020)
. shifted_gamma can be
used as the prior argument
to epim. This specified a shifted gamma prior on the negative of the
regression parameters. i.e. if there is no shift, the support is on the
negative half of the real line.
Flaxman S, Mishra S, Gandy A, Unwin HJT, Mellan TA, Coupland H, Whittaker C, Zhu H, Berah T, Eaton JW, Monod M, Perez-Guzman PN, Schmit N, Cilloni L, Ainslie KEC, Baguelin M, Boonyasiri A, Boyd O, Cattarino L, Cooper LV, Cucunubá Z, Cuomo-Dannenburg G, Dighe A, Djaafara B, Dorigatti I, van Elsland SL, FitzJohn RG, Gaythorpe KAM, Geidelberg L, Grassly NC, Green WD, Hallett T, Hamlet A, Hinsley W, Jeffrey B, Knock E, Laydon DJ, Nedjati-Gilani G, Nouvellet P, Parag KV, Siveroni I, Thompson HA, Verity R, Volz E, Walters CE, Wang H, Wang Y, Watson OJ, Winskill P, Xi X, Walker PGT, Ghani AC, Donnelly CA, Riley SM, Vollmer MAC, Ferguson NM, Okell LC, Bhatt S, Team ICCR (2020). “Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe.” Nature. ISSN 1476-4687, doi: 10.1038/s41586-020-2405-7 .