_dta: 1. date_changes set up by Jean Roth , jroth@nber.org , 9 Feb 2018 ndc: 1. The National Drug Code (NDC) serves as a universal product identifier for human drugs and biologics. 2. Each NDC must be reported as an 11-digit code unique to the manufacturer of the specific drug or product. ndc13: 1. The National Drug Code (NDC) serves as a universal product identifier for human drugs and biologics. 2. Each NDC must be reported as an 11-digit code unique to the manufacturer of the specific drug or product. ndcdash: 1. The National Drug Code (NDC) serves as a universal product identifier for human drugs and biologics. 2. Each NDC must be reported as an 11-digit code unique to the manufacturer of the specific drug or product. obs: 5,436 vars: 8 9 Feb 2018 15:57 size: 375,084 (_dta has notes) ----------------------------------------------------------------------------------------- storage display value variable name type format label variable label ----------------------------------------------------------------------------------------- ndc str11 %11s * National Drug Code (NDC) ndc13 str13 %13s * National Drug Code (NDC) with Dashes change str23 %23s Change olddate int %td.. Old Date newdate long %td.. New Date fileyear int %9.0g Year Data File Source filemonth byte %9.0g Month Data File Source ndcdash str13 %13s * National Drug Code (NDC) with Dashes * indicated variables have notes ----------------------------------------------------------------------------------------- Sorted by: ndc change olddate newdate