| Value | Category | 
                                    
                    
                        | 1 | master only (1) | 
                                    
                    
                        | 2 | using only (2) | 
                                    
                    
                        | 3 | matched (3) | 
                                    
                    
                        | 4 | missing updated (4) | 
                                    
                    
                        | 5 | nonmissing conflict (5) | 
                            
            Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.