Help regarding the stata coding

[SAUMYA AWASTHI]

I need your help regarding the code for multilevel modelling that I am referring to but it is not running from couple of days. The outcome variable is height whose variation I am about to see at individual, household, district and the state level. The code that I am running is unable to get processed as it is showing the error of "error obtaining the robust variances".
I am attaching the code which I am using for your consideration.
I shall be obliged if you can please help me out with this.

Code:
setmaxiter 100
xtmixed ht wt v212 i.v149 WEIGHT_FOR_AGE [pweight = v005] || new_code: GROWTH GROWTH_RATE || sdistri: dist_lit dist_urban || v002: i.v190 i.v025, nostderr

[Phil Bromiley]

Welcome to Statalist. You didn't get a quick response. You'll increase your chances of a useful answer by following the FAQ on asking questions - provide Stata code in code delimiters, readable Stata output, and sample data using dataex. Being able to replicate your problem is extremely helpful in diagnosing data-related problems. It would also help to know what version of Stata you're running - in Stata 15, xtmixed has been replaced by mixed. Since I currently only have the version 15 documentation on my computer, I can't even look up xtmixed's documentation. I wonder why Stata is concerned with robust variances when you haven't asked for robust standard errors (but this could reflect my ignorance - I don't do multi-level models).

Since I can't directly diagnose your problem, let me offer some ideas. First, I'd check that you're not including too many effects relative to the number of observations you have per individual etc. [Without any idea what is in v190, v205, etc., you might have created too many random effects relative to the data structure.] Second, I'd start with a simpler model and then work up.

[SAUMYA AWASTHI]

I am using stata version 14. The code that I am asking is for studying the variation of height at individual, household, district and the state level. The data used is from NFHS-4 which has the independent variables as weight, age at first birth, wealth index, educational attainment, type of residence, gdp growth and growth rate i have included and at the district level i have included the percentage of literacy and urbanisation. I am trying to run the multilevel modelling for this but its not working. I am still in delimma whether to include ddistrict and state as district wise will become the stratas for popultaion. Please help me out regarding the same