Stata undocumented commands and options

Stata undocumented commands and options
Stata undocumented/obsolete commands and options are usually used by limited people such as Stata programmers of StataCorp in developing Stata. However, sometimes I find they are quite handy.

• Analyzing survey data: -svygen- (generating adjusted sampling weights), -svycal- (calibration-adjusted sampling weights)
• Generating the estimate variables of a graph: - twoway__function_gen-, -twoway__histogram_gen-, -twoway__kdensity_gen-
• Calculating margins: -margins, gen()- (create margin-response variables in the current dataset), -margins, saving()- (save margins results to a dataset)
• Programming: -set buildfvinfo- (build extra factor-variables information into parameter estimates), -_coef_table- (displaying estimation results)
• finding more: A list of Stata undocumented command
• -vce()- options and options for survey data analysis: -vce(svy)-  and -vce(unconditional)- are obsolete options of -vce(linearized)-

verification or validation

Verification or Validation

• Verification and validation are quite different and used for different purposes. For example, verification answers, "Am I building the model right?", and validation answers, "Am I building the right model?"
• Wikipedia: Verification and validation of computer simulation models
• Wikipedia: Verification and validation
• Verification: The evaluation of whether or not a product, service, or system complies with a regulation, requirement, specification, or imposed condition. It is often an internal process
• Validation: The assurance that a product, service, or system meets the needs of the customer and other identified stakeholders. It often involves acceptance and suitability with external customers.

Stata: output and reuse the estimates of histogram

Stata: Output and reuse the estimates of a histogram
Sometimes we would like to export the estimates of a histogram and make a histogram plot using other software such as Excel.  The undocumented command - twoway__ histogram_gen - can help.

• Stata tip 20: Generating histogram bin variables, for example (modified):
• sysuse auto,clear
• histogram weight, percent bin(20)
• twoway__histogram_gen weight, bin(20) percent gen (hvalue xvalue, replace)
• twoway bar hvalue xvalue, barwidth(.15) bstyle(histogram)
• list hvalue xvalue if !missing(hvalue), sum(hvalue) clean
• or, you can copy columns from the "Data Editor" window and paste them into Excel sheet.
• or use - serset -, the data in the .gph file are stored in the serset format
• sysuse auto,clear
• histogram weight, percent width(100)
• preserve
• serset use,clear
• then, you can copy the first and third columns (such as __000001, __000003) from the "Data Editor" window and paste them into an Excel sheet.
• restore
• - grexport - a user-written ado file, an alternative to -graph export-
• sysuse auto,clear
• histogram weight, percent width(100)
• grexport, list //list results in the result window