Update cSTM_Tutorial_Intro.Rmd

Author: feralaes

manuscript/cSTM_Tutorial_Intro.Rmd

@@ -827,7 +827,7 @@ ceac_obj$Strategy <- ordered(ceac_obj$Strategy, v_names_str)
 elc_obj <- calc_exp_loss(wtp = v_wtp, psa = l_psa)
 ```
 
-To conduct the PSA of the CEA using the time-independent Sick-Sicker cSTM, we sampled `r comma(n_sim)` parameter sets from their distributions. For each of the parameters, we assumed commonly used distributions based on the type of parameters. For example, gamma for transition rates, lognormal for hazard ratios, and beta for utility weights.[@Parmigiani1997;@Parmigiani2002a;@Briggs2002;@Hunink2014] For each sampled parameter set, we simulated the cost and effectiveness of each strategy. Results from a PSA can be represented in various ways. For example, the joint distribution, 95% confidence ellipse, and the expected values of the total discounted costs and QALYs for each strategy can be plotted in a cost-effectiveness scatter plot (Figure \@ref(fig:CE-scatter)),[@Briggs2002] where each of the `r comma(n_sim)` simulations are plotted as a point in the graph. The CE scatter plot for CEA using the time-independent model shows that strategy AB has the highest expected costs and QALYs. Standard of care has the lowest expected cost and QALYs. Strategy B is more effective and least costly than Strategy A. Strategy A is a strongly dominated strategy.
+To conduct the PSA of the CEA using the time-independent Sick-Sicker cSTM, we sampled `r comma(n_sim)` parameter sets from their distributions. We assumed commonly used distributions to describe their uncertainty for each type of parameter. For example, gamma for transition rates, lognormal for hazard ratios, and beta for utility weights.[@Parmigiani1997;@Parmigiani2002a;@Briggs2002;@Hunink2014] For each sampled parameter set, we simulated the cost and effectiveness of each strategy. Results from a PSA can be represented in various ways. For example, the joint distribution, 95% confidence ellipse, and the expected values of the total discounted costs and QALYs for each strategy can be plotted in a cost-effectiveness scatter plot (Figure \@ref(fig:CE-scatter)),[@Briggs2002] where each of the `r comma(n_sim)` simulations are plotted as a point in the graph. The CE scatter plot for CEA using the time-independent model shows that strategy AB has the highest expected costs and QALYs. Standard of care has the lowest expected cost and QALYs. Strategy B is more effective and least costly than Strategy A. Strategy A is a strongly dominated strategy.
 
 ```{r CE-scatter, echo=FALSE, fig.cap='Cost-effectiveness scatter plot.', message=FALSE, warning=FALSE, fig.pos="H"} 
 # CEAC & CEAF plot