What is data?

Your phone counts your steps, the supermarket registers every purchase, and a weather station measures the temperature every few minutes. Data is created everywhere. But what exactly is data? The shortest answer: recorded observations. As soon as someone or something writes down, stores or measures an observation, data has been created.

Observations that last

Humans have been collecting data for thousands of years. A shepherd carving a notch into a stick for every sheep is creating data. A tally list on a blackboard, a diary of fever readings, a shop receipt: all of it is data. Only the speed is new. A modern sensor can record thousands of measurements per second without getting tired. The principle has stayed the same though: an observation is recorded so that it can be looked at, compared and counted later.

Data is not yet information

The number 39.2 is meaningless on its own. Only when you know that it is a child's body temperature in degrees Celsius does it become information: the child has a fever. Data is the raw material. Information emerges when you put data into context and interpret it. That is why having lots of data is not enough. If you cannot make sense of data, you end up knowing no more than before. Exactly this skill of reading data correctly is called data literacy, and it can be learned.

In the end it is all numbers

Computers store everything as numbers, more precisely as sequences of zeros and ones. A single zero or one is called a bit, eight bits together form a byte. A letter like a or B takes up exactly one byte in a simple text file, characters like ä or an emoji need more. Photos, music and videos are ultimately nothing but enormous columns of numbers too: every pixel and every sound is translated into numbers. For larger amounts there are handy units: 1000 bytes make a kilobyte, 1000 kilobytes a megabyte, 1000 megabytes a gigabyte. Some programs count in steps of 1024 instead, which is why they show slightly different numbers for the same file. Here we always use 1000.

Why this matters to you

If you understand what data is and how it comes about, you are harder to fool. Statistics in the news, recommendations from apps, promises about artificial intelligence: behind all of it lies data that somebody collected somehow. Data is neither good nor evil, it is a tool. The interesting question is always who collected it, how complete it is and what can honestly be concluded from it.