{
    "$id": "http://ihsn.org/schemas/nada/ddi_variable.json",
    "type": "object",
    "definitions": {},
    "$schema": "http://json-schema.org/draft-07/schema#",
    "properties": {
        "file_id": {
            "type": "string",
            "title": "File ID e.g. F1",
            "description": "File to which the variable belongs"
        },
        "vid": {
            "type": "string",
            "title": "Variable unique ID",
            "description": "Unique variable ID e.g. V1, V2"
        },
        "name": {
            "type": "string",
            "title": "Variable name"
        },
        "labl": {
            "type": "string",
            "title": "Variable label"
        },
        "var_intrvl": {
            "type": "string",
            "title": "Interval type",
            "description": "indicates the interval type; options are discrete or continuous.",
            "enum": ["discrete", "contin"]
        },
        "var_dcml": {
            "type": "string",
            "title": "Variable decimal points",
            "description": "Number of decimal points in the variable"
        },
        "var_wgt": {
            "type": "integer",
            "title": "Weight",
            "description": "indicates whether the variable is a weight"
        },
        "var_start_pos": {
            "type": "integer",
            "title": "Variable start position"
        },
        "var_end_pos": {
            "type": "integer",
            "title": "Variable end position"
        },
        "var_width": {
            "type": "integer",
            "title": "Variable width"
        },
        "var_imputation": {
            "type": "string",
            "title": "Imputation"
        },
        "var_security": {
            "type": "string",
            "title": "Security"
        },
        "var_respunit": {
            "type": "string",
            "title": "Source of information"
        },
        "var_qstn_preqtxt": {
            "type": "string",
            "title": "Pre-question text",
            "description": "Text describing a set of conditions under which a question might be asked."
        },
        "var_qstn_qstnlit": {
            "type": "string",
            "title": "Literal question"
        },
        "var_qstn_postqtxt": {
            "type": "string",
            "title": "Post-question text"
        },
        "var_qstn_ivulnstr": {
            "type": "string",
            "title": "Interviewer instructions"
        },
        "var_universe": {
            "type": "string",
            "title": "Universe"
        },
        "var_sumstat": {
            "type": "array",
            "description": "One or more statistical measures that describe the responses to a particular variable and may include one or more standard summaries, e.g., minimum and maximum values, median, mode, etc. \n\n The attribute 'type' denotes the type of statistics being shown: mean, median, mode, valid cases, invalid cases, minimum, maximum, or standard deviation.",
            "items": {
                "type": "object",
                "properties": {
                    "type": {
                        "type": "string",
                        "title": "Type"
                    },
                    "value": {
                        "type": "string",
                        "title": "Value"
                    }
                }
            }
        },
        "var_txt": {
            "type": "string",
            "title": "Variable description"
        },
        "var_catgry": {
            "type": "array",
            "title": "Categories",
            "items": {
                "type": "object",
                "properties": {
                    "value": {
                        "type": "string",
                        "title": "Value"
                    },
                    "label": {
                        "type": "string",
                        "title": "Label"
                    },
                    "stats": {
                        "type": "array",
                        "title": "Category statistics",
                        "description": "Category level statistics e.g. frequency",
                        "items": {
                            "type": "object",
                            "properties": {
                                "type": {
                                    "type": "string",
                                    "title": "Type",
                                    "description": "Type such as frequency, percent, etc"
                                },
                                "value": {
                                    "type": "string",
                                    "title": "Value"
                                }
                            }
                        }
                    }
                }
            }
        },
        "var_codinstr": {
            "type": "string",
            "title": "Recoding and derivation"
        },
        "var_concept": {
            "type": "array",
            "title": "Concepts",
            "items": {
                "type": "object",
                "properties": {
                    "title": {
                        "title": "Concept",
                        "type": "string"
                    },
                    "vocab": {
                        "title": "Vocabulary",
                        "type": "string"
                    },
                    "uri": {
                        "title": "Vocabulary URI",
                        "type": "string"
                    }
                },
                "required": [
                    "value"
                ]
            }
        },
        "var_format": {
            "type": "object",
            "title": "Variable format",
            "description": "The technical format of the variable in question. Attributes for this element include: 'type', which indicates if the variable is character or numeric; 'formatname,' which in some cases may provide the name of the particular, proprietary format actually used; 'schema,' which identifies the vendor or standards body that defined the format (acceptable choices are SAS, SPSS, IBM, ANSI, ISO, XML-data or other); 'category,' which describes what kind of data the format represents, and includes date, time, currency, or 'other' conceptual possibilities.",
            "properties": {
                "type": {
                    "type": "string",
                    "title": "Type"
                },
                "name": {
                    "type": "string",
                    "title": "Name"
                },
                "value": {
                    "type": "string",
                    "title": "Value"
                }
            }
        },
        "var_notes": {
            "type": "string",
            "title": "Variable notes"
        }
    },
    "required": ["vid", "file_id", "name", "labl"]
}