From the resource: "This document presents the definition of formative assessment and identifies and explains the five attributes of effective formative assessment. One key feature of this definition is its requirement that formative assessment be regarded as a process rather than a particular kind of assessment. In other words, there is no such thing as 'a formative test.' Instead, there are a number of formative assessment strategies that can be implemented during classroom instruction. These range from informal observations and conversations to purposefully planned instructionally embedded techniques designed to elicit evidence of student learning to inform and adjust instruction."
This resource provides an excellent overview of formative assessment. It includes a definition of formative assessment and in-depth descriptions of each attribute of formative assessment. The attributes relate to use of learning progressions, learning goals, success criteria, descriptive feedback, peer and self-assessment, and collaboration.