I am new to stata so hope this question is not too naive. I am working with
a file containing a mix of cases, some with single observations, others
with multiple observations. Overall file has approx. 3600 cases with over
15500 observations. My plan is to model these data using survival analysis
techniques. Generally I am exploring predictions about how the probability
of a given type of change is influenced by elapsed time since a prior
change of the same type. However, when I attempt to set up the data using
snapspan, I end up with almost complete missing data (excepting for id
value and failure indicator) for cases with single observations as well as
for the first record in cases with multiple observations. Is there away to
correct this, or to avoid having it happen? The replace missing values
protocol does not work for the single observations cases, and generally is
not adequate for first record in cases with multiple observations for
various reasons. e.g., it drops one value from a cumulative frequency
variable and throws off the appropriate alignment for time-varying
covariates. Thanks in advance for any suggestions.
