Quantum deals with three types of record: ordinary, multicard and multicard with trailer cards.

These are strings of codes and numbers, one per respondent, up to a maximum of 32,767 characters per respondent.

When data originates from punch card format and each questionnaire requires more than 80 columns, the data is spread over several cards. So that all cards belonging to a particular respondent may be easily identified, each questionnaire is assigned a serial number which is entered as part of the data for each card. Within this, each card has a unique card type or card number to distinguish it from others in the group. It is important that both the serial number and card type be in the same relative positions on all cards in the file, since this is the only way that Quantum can tell which data belongs to which respondent.

If the questionnaire serial number is in columns 1 to 4 of each card and the card type is in column 5, and you are looking at questionnaire 1005, you will see that it has two cards whose first five columns are 10051 and 10052 respectively. Quantum can deal with records that contain up to 327 cards per respondent.

Occasionally you might have multicard records in which each ‘card’ is greater than 80 columns. The notes that follow refer to multicard records of up to 100 columns per card.

For information on how Quantum deals with ‘cards’ of more than 100 columns, see Multicard records of more than 100 columns per card.

Sometimes a record contains very repetitive data which is tabulated over and over again in the same way. For example, a shopping survey may ask the respondent a series of identical questions for each store they visited. In this case, there may be a separate card for each store.

Processing this type of data is often easier if you treat all cards containing the same questions as if they were, in fact, one card with one card number. These cards are called trailer cards.

Thus, if the respondent visited five stores, and the questions about these stores are coded on a card 2, the record for that respondent would contain five cards of type 2. If demographic details were stored on a card 1, the whole record would be 6 cards in all. In Quantum, the demographic data would be described as the higher level and the stores as the lower level.

Another example of data gathered at different levels might be a travel survey in which respondents are asked about the places they visited and their method of travelling. The highest level may be demographic information about the respondents, the second level would be the various trips they made and the third level might be information about the various modes of transport they used. A chart of a record looks like this:

There are three groups of data at level 2 and eight groups of data at level 3.