hēRo3 keywords are special variables that are automatically created in every hēRo3 model. A listing of hēRo3 keywords is provided below. These keywords can drastically reduce the amount of work and time it takes to build a model in hēRo3. For example, the hēRo3 keyword, "state_time", tracks the number of cycles elapsed since entry into any given health state. Use of this keyword can greatly simplify the process of creating so-called “tunnel” states in Markov cohort models.
It is important to note that R is case-sensitive. Thus, for example, if you want hēRo3 to automatically calculate the complementary probability for a sum of transition probabilities, and you type in lower case “c” instead of capital “C”, your model will generate an error.
Name |
Description |
bc |
Base-case value for a given parameter. This keyword can only be used on the DSA Inputs and PSA Inputs pages. |
C |
Calculates complementary probability in a transition matrix or initial state probability. Can only be used on the Transitions and States pages. |
cycle_length_days |
Length of a model cycle, in days. |
cycle_length_weeks |
Length of a model cycle, in weeks. |
cycle_length_months |
Length of a model cycle, in months. |
cycle_length_years |
Length of a model cycle, in years. |
group |
Name of a patient group. Can be used in conditional statements to make a formula depend on group to which a patient belongs. |
model_time |
Number of cycles since start of a model. Counting begins with 1 in first cycle. |
model_day |
Time since start of model, in days. Is equal to model_time * cycle_length_days. |
model_week |
Time since start of model, in weeks. Is equal to model_time * cycle_length_weeks. |
model_month |
Time since start of model, in months. Is equal to model_time * cycle_length_months. |
model_year |
Time since start of model, in years. Is equal to model_time * cycle_length_years. |
state_time |
Number of cycles since entry into a given state. Counting begins with 1 for first cycle in the state. Can only be used in Markov Cohort models. |
state_day |
Time since entry into a state, in days. Equal to state_time * cycle_length_days. Can only be used in Markov Cohort models. |
state_week |
Time since entry into a state, in weeks. Equal to state_time * cycle_length_weeks. Can only be used in Markov Cohort models. |
state_month |
Time since entry into a state, in months. Equal to state_time * cycle_length_months. Can only be used in Markov Cohort models. |
state_year |
Time since entry into a state, in years. Equal to state_time * cycle_length_years. Can only be used in Markov Cohort models. |