RATS Files
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RATS (Regression Analysis of Time Series) is a general-purpose econometric and time series analysis package.  Stat/Transfer can read and write RATS Version 7-8 files. 


Standard extensions:  rat


Reading RATS Files

Unlike the rectangular file format of many of the programs supported by Stat/Transfer, RATS stores data in separate time-series of data, each of which can have differing start dates, frequencies and numbers of observations. Stat/Transfer makes these potentially very irregular data suitable for analysis in other software.   


First, every series is examined to determine which has the earliest start date.  The first observation in that series will determine the earliest row in the output dataset.   If all series have the same frequency, the data will be output with missing values substituted for missing values in series, if necessary, and a new date variable will be constructed to tag each row of the file.  If the series differ in frequencies, the most frequent series will determine the frequency of the output and less frequent series will have their data values duplicated, as necessary, to construct an output row.


Writing RATS Files

RATS supports only numeric types.  Therefore, when one transfers data to a RATS output file, all non-numeric variables (strings, dates, date/times and times) will be ignored. Stat/Transfer will create an output file with the number of time series variables equal to the number of numeric variables in the input file.


On output, by default, Stat/Transfer will look for the first date variable in the file (typically there will be only one).  Using that variable, it will determine the start date for each of the other series in the file.  It will also use that variable to autosense the frequency of the data.  In order for this to work, the data must be in ascending sorted order and the date variable must contain dates that can be described by the one of the supported frequencies: daily, weekly, monthly, quarterly, or annual.  Stat/Transfer will use the date from the first row and apply an autosensed or requested frequency.


In autosensing frequencies, Stat/Transfer is necessarily fairly rigid and will require that, for instance, annual data must start in January, monthly data begin on the first date of the month, weekly data occur at seven-day intervals and so on. 


If the default options are not suitable you can change Stat/Transfer's behavior by setting the options in the RATS section on the Options tab.


If your data occur with a specifiable frequency, but are less than completely regular, you can turn off autosensing and specify a daily, weekly, monthly or annual frequency.


If you have more than one date variable and want to specify a specific one for use in determining the start date and, if needed, frequency, you can select a specific variable from a list.  You can select a specific frequency even if you use a date variable to determine the start date.


Finally, if your file does not have a date variable in it at all, you can specify the start date and frequency.  In this case, a specific frequency must be specified.


Missing Values

Missing values are supported.

Output Variable Types

The output variable type that results from each target variable type is given in the following table:




Target Type

Output Type


byte

int

long

float

double

RATS double precision number


date

date/time

time

Not supported as series  (see text)