“... coloured diagrams and symbols are used instead of letters for the greater ease of learners.”
The Elements of Euclid, Oliver Bryne in 1847
The media ...
Data as a medium to design stands for  the representation of populations and measurement at scale.

The two relevant sources of data for design research are data from systems and data from surveys, which serve different purposes.

System data is especially reliable to reveal behavioral patterns at scale. Surveys find their strength in understanding intentions, perceptions and needs self-reported by respondents.

Data is prone to measurement biases and  intentional or unintentional false interpretation of findings.

Stories stand for relating to others in their individuality and our shared humanity.  

Listening to understand personal narratives, why people believe what they believe, they do what they do is quintessential, so we do not design solutions based on assumptions informed by our own experiences.

Stories stem not only from interviews but a wide variety of other methods like co-creation sessions, analogous research, observations and others.

Stories are not meant too provide averages but inspiration to design for the specific.

Design stands for iterating our ideas into concepts, prototypes, MVPs all the way to a final product or service.

Desgin is human-centered when informed by people’s explicit and implicit needs.  Design goes through iterations from low fidenlity to higher resolutions.

Design’s strength is to make talk real and its weakness is to commit too early to  solutions we’ve fallen in love with or rushed towards.
.... needs a process
... and statistics are used to reject or confirm hypothesis.

However, analysis can also be used in a generative, explorative way.
... is the distillation of large amounts of qualitative and quantitattive data into one coherent set of insights and principles.

Synthesis succedes any type of analysis. Synthesis also applies to making secondary research relevant. 
analysis then synthesis
Analysis and Synthesis are, strictly speaking,  in opposition. As Synthesis generates hypothesis while analysis tests hypothesis.

Design research is agnostic towards the strict separation as all collected data looks for contextual interpretation to make meaning for the next design iteration.
... tHAT TURNS INTO method
Qualitative methods go through synthesis to provide the insights to inspire and guide the subsequent design phase.
Qualitative interviews followed by synthesis guide the design of a survey. Survey data is analyzed and used as a screener to select participants for subsequent interviews.
... WHICH LEADS TO learning
Result of human-centered design informed by qualitative stories.
Result of cross-validated insights, “Hybrid Insights” validated by both, quantitative and qualitative data.
Classic approach to human-centered design research are iterations of qualitative research followed by design. Eventually making the final solutions human-centered.
Integrated qual-quant approach to create insights that have the depth to inform design and scale to inform business decisions.
Qualitatively informed human-centered designs are synthesized into artifacts. Artifacts are validated via concept based surveys confirming what design and parts thereof to prioritize for whom.
..... solving FOR the objectives of research, strategy, and design.
Oliver Bryne stated in his introduction: 

"The arts and sciences have become so extensive, that to facilitate their acquirement is of as much importance as to extend their boundaries.
Illustrations, if it does not shorten the time of study, will at least make it more agreeable.

This work has a greater aim than mere illustration; we do not introduce colors for the purpose of entertainment, or to amuse by certain combinations of tint and form, but to assist the mind in its research after truth, to increase the facilities of instruction, and to diffuse permanent knowledge."  

The Elements of Euclid,  1847

One may assume that the used geometries are inspired by Bauhaus design principles. When it relates to the graphic design, that may very well be true.

However, the true inspiration was drawn from a book created by Oliver Bryne in 1847. His goal, in his own words was: “... coloured diagrams and symbols are used instead of letters for the greater ease of learners.”  And to quote the NYTimes:”Every graphic designers, book lover and math nerd will be awestruck.”

The following iconography is an attempt to use this inspiration to start creating a guide of symbols for better signification of design research methods, processes and resutling approaches. Eventually organizing the shared  anecdotes from the field thematically.
Design Research is comprised of a wide variety of methods to understand human-centered needs in the service of creating and improving designs. The learnings inform all types of design ranging from graphic, to interaction, system and even business design.
Full-stack Design Research
Full-stack design research standss for being agnostic to tools and methods and instead selecting methods and sequences thereof that are seen to have the highest probability to lead to truthful results that address the desired objectives.
UX Research
User experience research is a subset of design reserach as it predominantely concerns itself with solving for existing and perhaps prospective users of a service or product. It concerns itself more with concrete and less sith broad strategic systemic solutions.
At times we hear that data tells us the WHAT and stories tell us the WHY people do what they do.

Taking this as true it implies that the knowledge of data and stories will deliver both.

The essence of human-centered design .
Data as medium to design at scale, prioritized and validate.