xii
producing information on a property of that object in the form of values of that
property” (Sect. 2.2). I will not attempt to unpack this statement here, as the authors
do so quite thoroughly, but I will note some of the implications they discuss. These
necessary conditions encompass classical and derived physical measures. They do
not require values of either objects’ properties or empirical observations to satisfy
particular mathematical forms. A property characterized by categorical values, for
example, could also be shown to be measurable under the framework proposed in
this book.
I underscore and will return to two final general implications of their necessity
conditions that the authors draw that I consider central to developing a contemporary understanding of educational measurement. The first is existence: “[T]he critical question is how we know that a property exists, and therefore that it meets at
least the most basic criterion for measurability” (Sect. 6.6.1). The second is that
more is needed than a discerned input-output relationship of objects and effects:
“[A]ny purely black box model cannot adequately account for all relevant features
of measurement, and thus is not sufficient for the purpose of understanding the quality of measurement results” (Sect. 7.1).
Neither will I unpack sufficient conditions for measurability of a property; they
too deserve further explanation, which the authors provide quite lucidly. Objectivity
and intersubjectivity are key concepts. Objectivity is the extent to which the conveyed information is about the property under measurement and nothing else (an
ideal, to be sure; the authors discuss and illustrate avenues by which it may be
examined, critiqued, and quantified in given situations). Intersubjectivity addresses
the goal that the conveyed information is interpretable in the same way by different
persons in different places and times (similarly explicated and illustrated).
Taking these conditions together, the authors propose taking the necessary and
sufficient conditions into account, “measurement is an empirical and informational
process that is designed on purpose, whose input is an empirical property of an
object, and that produces explicitly justifiable information in the form of values of
that property” (Sect. 8.3.4). In particular, “a property is measurable if and only if
there exists a property-related process fulfilling these conditions” (Sect. 7.1).
The authors call our attention to the pragmatic nature of measurement as it is
actually used, with regard to defining measures, devising instruments, calibrating
the values, and justifying their use for given purposes under given conditions (typically less broad in psychosocial domains than physical domains, for reasons we will
see in the next section). Objectivity and intersubjectivity are ideals, never perfectly
realized. How well can we satisfy them in a particular case, and with what strength
of grounding for the nature of a property and the processes by which it produces
effects? What is the strength of the arguments, the situated fidelity of the models,
and the quality of evidence, as evaluated within the common framework that this
book affords? Work is required in each case; answers are neither assured nor guaranteed uncontroversial, but we can hold our debates in a shared language and system.
By implication, and as seen historically, advances in theory and instrumentation
can strengthen our arguments for a measure and measurements thereof, or instead
relegate a project to the dustbin. We may transform our understanding of underlying
Foreword
producing information on a property of that object in the form of values of that
property” (Sect. 2.2). I will not attempt to unpack this statement here, as the authors
do so quite thoroughly, but I will note some of the implications they discuss. These
necessary conditions encompass classical and derived physical measures. They do
not require values of either objects’ properties or empirical observations to satisfy
particular mathematical forms. A property characterized by categorical values, for
example, could also be shown to be measurable under the framework proposed in
this book.
I underscore and will return to two final general implications of their necessity
conditions that the authors draw that I consider central to developing a contemporary understanding of educational measurement. The first is existence: “[T]he critical question is how we know that a property exists, and therefore that it meets at
least the most basic criterion for measurability” (Sect. 6.6.1). The second is that
more is needed than a discerned input-output relationship of objects and effects:
“[A]ny purely black box model cannot adequately account for all relevant features
of measurement, and thus is not sufficient for the purpose of understanding the quality of measurement results” (Sect. 7.1).
Neither will I unpack sufficient conditions for measurability of a property; they
too deserve further explanation, which the authors provide quite lucidly. Objectivity
and intersubjectivity are key concepts. Objectivity is the extent to which the conveyed information is about the property under measurement and nothing else (an
ideal, to be sure; the authors discuss and illustrate avenues by which it may be
examined, critiqued, and quantified in given situations). Intersubjectivity addresses
the goal that the conveyed information is interpretable in the same way by different
persons in different places and times (similarly explicated and illustrated).
Taking these conditions together, the authors propose taking the necessary and
sufficient conditions into account, “measurement is an empirical and informational
process that is designed on purpose, whose input is an empirical property of an
object, and that produces explicitly justifiable information in the form of values of
that property” (Sect. 8.3.4). In particular, “a property is measurable if and only if
there exists a property-related process fulfilling these conditions” (Sect. 7.1).
The authors call our attention to the pragmatic nature of measurement as it is
actually used, with regard to defining measures, devising instruments, calibrating
the values, and justifying their use for given purposes under given conditions (typically less broad in psychosocial domains than physical domains, for reasons we will
see in the next section). Objectivity and intersubjectivity are ideals, never perfectly
realized. How well can we satisfy them in a particular case, and with what strength
of grounding for the nature of a property and the processes by which it produces
effects? What is the strength of the arguments, the situated fidelity of the models,
and the quality of evidence, as evaluated within the common framework that this
book affords? Work is required in each case; answers are neither assured nor guaranteed uncontroversial, but we can hold our debates in a shared language and system.
By implication, and as seen historically, advances in theory and instrumentation
can strengthen our arguments for a measure and measurements thereof, or instead
relegate a project to the dustbin. We may transform our understanding of underlying
Foreword