Data are recorded on a data sheet with one row for each response and one column for each question, and tallies become a frequency table whose total must match the number of rows. Ways of collecting data differ in how much storage they need, how much detail they collect and how often they take a sample. Metadata are data about data; changing metadata does not change the data, and metadata help people find, organize and manage information. One source often does not hold all the data needed, so sources may be combined.