17-16. The data processing method described in 17,

in which the extraction step includes a word string extraction unit that analyzes text data to be analyzed and extracts a word string whose appearance frequency in the text data to be analyzed satisfies a predetermined condition among word strings detected in the text data to be analyzed, and

the output unit outputs information regarding the extracted word string.

18. A program causing a computer to function as:

an extraction unit that analyzes data to be analyzed and extracts a subject whose appearance frequency in the data to be analyzed satisfies a predetermined condition among subjects detected in the data to be analyzed; and an output unit that outputs information regarding the extracted subject.

18-2. The program described in 18,

in which the extraction unit is caused to function as a person extraction unit that analyzes moving image data to be analyzed and extracts a person whose appearance frequency in the moving image data to be analyzed satisfies a predetermined condition among persons detected in the moving image data to be analyzed, and

in which the output unit outputs information regarding the extracted person.

18-3. The program described in 18-2,

in which the moving image data to be analyzed includes a plurality of pieces of child data captured at a plurality of places different from each other different from each other, and