diff --git a/docs/src/tutorials/uciwwiehr_model_fitting_forecast.md b/docs/src/tutorials/uciwwiehr_model_fitting_forecast.md
index 072feb1..8823cf9 100644
--- a/docs/src/tutorials/uciwwiehr_model_fitting_forecast.md
+++ b/docs/src/tutorials/uciwwiehr_model_fitting_forecast.md
@@ -41,7 +41,8 @@ data_hosp = df.hosp
 data_wastewater = df.log_ww_conc
 obstimes_hosp = df.obstimes
 obstimes_wastewater = df.obstimes
-param_change_times = 1:7:length(obstimes) # Change every week
+max_obstime = max(length(obstimes_hosp), length(obstimes_wastewater))
+param_change_times = 1:7:max_obstime) # Change every week
 priors_only = false
 n_samples = 50
 forecast = true
diff --git a/docs/src/tutorials/uciwwiehr_model_fitting_no_forecast.md b/docs/src/tutorials/uciwwiehr_model_fitting_no_forecast.md
index acce434..ad56710 100644
--- a/docs/src/tutorials/uciwwiehr_model_fitting_no_forecast.md
+++ b/docs/src/tutorials/uciwwiehr_model_fitting_no_forecast.md
@@ -48,7 +48,8 @@ data_hosp = df.hosp
 data_wastewater = df.log_ww_conc
 obstimes_hosp = df.obstimes
 obstimes_wastewater = df.obstimes
-param_change_times = 1:7:length(obstimes) # Change every week
+max_obstime = max(length(obstimes_hosp), length(obstimes_wastewater))
+param_change_times = 1:7:max_obstime) # Change every week
 priors_only = false
 n_samples = 50
 forecast = false