``start_column``
----------------

- Available in: CoxPH
- Hyperparameter: no

Description
~~~~~~~~~~~

This option is used to specify the name of an integer column in the **source** data set representing the start time. If supplied, then the value of the **start_column** must be strictly less than the **stop_column** in each row.

Related Parameters
~~~~~~~~~~~~~~~~~~

- `stop_column <stop_column.html>`__


Example
~~~~~~~

.. example-code::
   .. code-block:: r

    library(h2o)
    h2o.init()
    # import the heart dataset
    heart <- h2o.importFile("http://s3.amazonaws.com/h2o-public-test-data/smalldata/coxph_test/heart.csv")

    # set the predictor name and response column
    x <- "age"
    y <- "event" 

    # set the start and stop columns
    start <- "start"
    stop <- "stop"

    # train your model
    coxph.h2o <- h2o.coxph(x=x, event_column=y, 
                           start_column=start, stop_column=stop, 
                           training_frame=heart.hex)

    # view the model details
    coxph.h2o
    Model Details:
    ==============

    H2OCoxPHModel: coxph
    Model ID:  CoxPH_model_R_1527700369755_2 
    Call:
    "Surv(start, stop, event) ~ age"

          coef exp(coef) se(coef)    z     p
    age 0.0307    1.0312   0.0143 2.15 0.031

    Likelihood ratio test=5.17  on 1 df, p=0.023
    n= 172, number of events= 75