if(!requireNamespace("fabricatr", quietly = TRUE)) {
install.packages("fabricatr")
}
library(CausalQueries)
library(fabricatr)
library(knitr)
Generating: To make a model you need to provide a
DAG statement to make_model
.
For instance
"X->Y"
"X -> M -> Y <- X"
or"Z -> X -> Y <-> X"
.# examples of models
<- make_model("X -> Y")
xy_model <- make_model("Z -> X -> Y <-> X") iv_model
Graphing: Once you have made a model you can inspect the DAG:
plot(iv_model)
Inspecting: The model has a set of parameters and a default distribution over these.
|> grab("parameters_df") |> kable() xy_model
param_names | node | gen | param_set | nodal_type | given | param_value | priors |
---|---|---|---|---|---|---|---|
X.0 | X | 1 | X | 0 | 0.50 | 1 | |
X.1 | X | 1 | X | 1 | 0.50 | 1 | |
Y.00 | Y | 2 | Y | 00 | 0.25 | 1 | |
Y.10 | Y | 2 | Y | 10 | 0.25 | 1 | |
Y.01 | Y | 2 | Y | 01 | 0.25 | 1 | |
Y.11 | Y | 2 | Y | 11 | 0.25 | 1 |
Tailoring: These features can be edited using
set_restrictions
, set_priors
and
set_parameters
. Here is an example of setting a
monotonicity restriction (see ?set_restrictions
for
more):
Here is an example of setting a monotonicity restriction (see
?set_restrictions
for more):
<-
iv_model |> set_restrictions(decreasing('Z', 'X')) iv_model
Here is an example of setting priors (see ?set_priors
for more):
<-
iv_model |> set_priors(distribution = "jeffreys")
iv_model #> No specific parameters to alter values for specified. Altering all parameters.
Simulation: Data can be drawn from a model like this:
<- make_data(iv_model, n = 4)
data
|> kable() data
Z | X | Y |
---|---|---|
0 | 0 | 0 |
0 | 0 | 1 |
1 | 1 | 0 |
1 | 1 | 0 |
Updating: Update using update_model
.
You can pass all rstan
arguments to
update_model
.
<- fabricatr::fabricate(N = 100, X = rbinom(N, 1, .5), Y = rbinom(N, 1, .25 + X*.5))
df
<-
xy_model |>
xy_model update_model(df, refresh = 0)
Inspecting: You can access the posterior distribution on model parameters directly thus:
|> grab("posterior_distribution") |>
xy_model head() |> kable()
X.0 | X.1 | Y.00 | Y.10 | Y.01 | Y.11 |
---|---|---|---|---|---|
0.4466199 | 0.5533801 | 0.1636397 | 0.1492105 | 0.6489364 | 0.0382134 |
0.4789333 | 0.5210667 | 0.1054836 | 0.1500004 | 0.6119007 | 0.1326153 |
0.4718292 | 0.5281708 | 0.3269378 | 0.0828981 | 0.5177509 | 0.0724132 |
0.4542422 | 0.5457578 | 0.3249261 | 0.0082074 | 0.5356523 | 0.1312142 |
0.4871812 | 0.5128188 | 0.2682652 | 0.0363204 | 0.5857549 | 0.1096594 |
0.4524378 | 0.5475622 | 0.1585780 | 0.0936094 | 0.7336056 | 0.0142069 |
where each row is a draw of parameters.
Querying: You ask arbitrary causal queries of the model.
Examples of unconditional queries:
|>
xy_model query_model("Y[X=1] > Y[X=0]", using = c("priors", "posteriors")) |>
kable()
query | given | using | case_level | mean | sd | cred.low | cred.high |
---|---|---|---|---|---|---|---|
Y[X=1] > Y[X=0] | - | priors | FALSE | 0.248373 | 0.1904903 | 0.0076384 | 0.6923843 |
Y[X=1] > Y[X=0] | - | posteriors | FALSE | 0.587883 | 0.0888942 | 0.4039806 | 0.7455046 |
Examples of conditional queries:
|>
xy_model query_model("Y[X=1] > Y[X=0]", using = c("priors", "posteriors"),
given = "X==1 & Y == 1") |>
kable()
query | given | using | case_level | mean | sd | cred.low | cred.high |
---|---|---|---|---|---|---|---|
Y[X=1] > Y[X=0] | X==1 & Y == 1 | priors | FALSE | 0.4963863 | 0.2859801 | 0.0251328 | 0.9727251 |
Y[X=1] > Y[X=0] | X==1 & Y == 1 | posteriors | FALSE | 0.8572202 | 0.0989188 | 0.6380308 | 0.9948683 |
Queries can even be conditional on counterfactual quantities. Here the probability of a positive effect given some effect:
|>
xy_model query_model("Y[X=1] > Y[X=0]", using = c("priors", "posteriors"),
given = "Y[X=1] != Y[X=0]") |>
kable()
query | given | using | case_level | mean | sd | cred.low | cred.high |
---|---|---|---|---|---|---|---|
Y[X=1] > Y[X=0] | Y[X=1] != Y[X=0] | priors | FALSE | 0.5037974 | 0.2908795 | 0.0276229 | 0.9754840 |
Y[X=1] > Y[X=0] | Y[X=1] != Y[X=0] | posteriors | FALSE | 0.8650345 | 0.0733055 | 0.7222992 | 0.9929217 |