Beginnings Guides Blog
Let’s welcome the new year with some new
thinking about measuring health literacy.
It’s hard to say exactly what electricity
is, but if the lights are on, we know we’ve got it. And we
measure electricity by the light it produces. So it is with health literacy. It
is hard to say just what health literacy is, but we know it by its
consequences, and we can measure those consequences.
Services utilization, behaviors, self-care
Two recent systematic reviews and concept analyses (Sykes 2013,
Sorenson 2012) identified the consequences of health literacy. Both studies found the most frequently
reported consequences of health literacy are improved use of services,
behaviors, and self-care. These consequences reflect how people use their
health literacy skills in everyday life and what they actually do for health with the information and
support available to them.
Although these consequences are supposed or anticipated rather than
evidence-based (Sykes 2013), the documented presence of these consequences
would indicate that the person possesses and has used health literacy skills to
produce them. Studies using the Life Skills Progression instrument to assess
maternal heath literacy are building the evidence base.
The LSP Maternal
Health Literacy Scales rate mothers health literacy by their health and
healthcare-related actions practices and behaviors. Sequential measures show
change —improvement or regression. The LSP Healthcare Literacy Scale uses 9 items to rate
mothers’ use of information, emergency services, medical and dental
care and preventive services for herself and her child. The Selfcare Literacy
Scale uses five items to assess risk behaviors and selfcare practices. Three published studies using LSP data on three different cohorts
of mother-child dyads provide
evidence that mothers supported by home visitors trained to promote maternal
heath literacy produced the consequences of health literacy at increasing levels
over 12-18 months. So the recent
analyses of the consequences of health literacy confirm earlier findings that
the LSP can be used as meaningful
measure of MHL.
Next: the recently identified unique consequences of critical
health literacy add weight to our theory that critical thinking skill,
particularly reflection, is the active ingredient in health literacy that enables mothers (and others) to
transform their decisions into health promoting actions and outcomes. Stay
K. Van den Broucke S, Fullam J,
Doyle G, Pelikan J, et. al. (2012). Health Literacy and Public Health: A
systematic review and integration of definitions and models. BMC Public
S, Willis J, Rowlands G & Popple K. (2013). Understanding critical
literacy: a concept analysis. Biomed Central Public Health:13:150.
Smith, S. A., & Moore, E. J. (2012). Health literacy and depression in the context of home visitation. Maternal and Child Health Journal, 16, 1500-1508.
Carroll LN, Smith SA & Thomson NR. (2014). The Parents as Teachers Health Literacy Demonstration Project: Integrating an Empowerment Model of Health Literacy Promotion into Home-Based Parent Education. Health Promotion Practice
pii: 1524839914538968. [Epub ahead of print]. Available on Internet at: http://hpp.sagepub.com/content/early/2014/06/23/1524839914538968.abstract
Mobley S, Thomas S, Sutherland D, Hudgins, J, Ange B & Johnson M. (2014) Maternal Health Literacy Progression Among Rural Perinatal Women. Maternal Child Health J 18: 1881-1892.
Beginnings Pregnancy Guide 9th Edition Sold Out
The second printing of the 2014 is underway. The scan code that instantly links Beginnings
readers to additional prescreened information via the Internet on a mobile device has proved popular. In a survey of pregnant women in SC, we found that respondents rarely use toll free numbers; while nearly all reported finding health information online. The entire website
is available on your mobile device.
Websites Continue to Grow
Beginnings Guides had 155,00 visitors in 2014. The Center for Health Literacy Promotion had 55,000 visitors. The blogs were read by 100,00 including 6900 reads in the last 30 days. And we have 1310 Twitter followers. Kudos to Beginnings Webmother, Simone Snyder.
Most read blogs
(this one was on the most-read list for 2013, too)
Promoting Maternal Health Literacy Nationally & Internationally
Free Health Literacy Training Videos
We produced a series of training videos in collaboration with the National Network of Libraries of Medicine Pacific Northwest Region. This from the National Libraries Website:
Center for Health Literacy Promotion offers free training
Together with the National Network of Libraries of Medicine, the Center for Health Literacy Promotion has put together three short training sessions on understanding and promoting health literacy designed for social and health services providers and programs. Each session includes a short video, a pre- and post-test (with answer key), a handout, and a facilitator's guide. All three sessions and their resources are available to download or view for free online.
To view these resources, visit the Center for Health Literacy Promotion:
Published Article: Parents As Teachers Health Literacy Demonstration Project
Carroll LN, Smith SA & Thomson N (2014). Integrating an Empowerment Model of Health Literacy Promotion into Home-Based Parent Education. Health Promotion Practice
pii: 1524839914538968. [Epub ahead of print] Read the article
Guest editor, Curationis Special Edition:
This turned out to be a monumental work and an inspiring labor of love. It was a joy and a challenge to work with a dozen authors whose work is at the foundation of efforts in southern and eastern African countries to develop professional education curricula and build a workforce of nurses dedicated to care of children. With health systems only about 20 years old, this work is underway to differentiate care of children from care of adults. Therefore, the articles focus on issues in professional education and practice. There are many lessons we in the US can learn from their work to build a healthcare system grounded in child rights, and to effect systems change in the face of racism and limited resources. Curationis, a South African nursing journal has published the special edition online with free access for all. It will appear in print in 2015.
HARC VI Washington DC Nov 4-5
Family transitions precluded my travel to DC this year. But I was not totally absent. Linda Wollesen, developer of the LSP presented in my stead results of a study conducted in collaboration with Anne Turner and colleagues at University of Washington Northwest Center for Public Health Practice. Conclusion: parents can and do manage child oral health, even in the face of poverty, low education and limited English proficiency where service and supports to use them are in place. This is on the list to publish in 2015.
New & Contintuing in 2015
Worldwide Universities Health Literacy Network
in Sydney I worked with an awesome group scholars/practitioners/patient representatives to instigate an international collaboration on promoting health literacy as a personal and community asset. The group has joined with others who began similar talks in 2012 at the first Worldwide Universities Health Literacy Network meeting in Southampton, and expanded to include representatives of countries in Europe, Asia, Africa , South America (and me). The collaborators have been holding monthly meetings via Skype and are developing funding proposals to address maternal health literacy globally.
CenteringPregnacy Health Literacy Trial
This project continues. I got to visit the site of the comparison group, Greenville Health System, Greenville, SC. We're searching for a second site. Want to be an intervention site? Contact me!
Maternal Health Literacy: Untangling the "Web of Interaction"
The research project for 2015 is funded by the National Library of Medicine. The study addresses an urgent need to determine what promotes maternal health literacy, especially in historically underserved poverty populations. We are identifying factors in the home and family context that influence mothers'health literacy, and how those factors interact. Understanding the context in which mothers use information and services for personal and child health can guide intervention design, tailoring and evaluation. We are looking for ways to visualize data to suggest points of intervention and help home visitors to answer the ever-vexing question: where to begin?
Previously in this Space,
I suggested that efforts to promote
health literacy are better guided by a salutogenic model
that asks, What enables a
person to move toward health? or what enables a person to take action for
health? That’s true in
health promotion. But a person uses the health literacy skill set in various
combinations to accomplish different health task in multiple health contexts.
No single approach will get us to our envisioned health literate society.
Need for an integrated Approach
A new salutogenic perspective and
approach to health literacy needs to complement rather than replace the
dominant pathogenic approach.
Nearly everyone will at some time find themselves in need of care that
only hospitals and healthcare organizations can provide. The pathogenic
approach is appropriate and necessary in healthcare contexts.
In addition, with chronic
disease/disability steadily increasing and accounting for nearly half of all
health loss (Lytton, 2013), and nearly 80% of all health costs in the US
(Budenheimer 2009) continuing attention to risk factors and preventive
practices is necessary and will remain so.
Still, the number and variety of
risks, and the number and variety of conditions that constrain health choices,
are so vast that achieving health literacy as defined in the pathogenic model
is nearly implausible (Lytton 2013). A salutogenic approach is needed to
clarify where, when, and how mothers, and others, can take effective action to
achieve, maintain and enhance good health.
Domains of Health Literacy
Sorenson et al (2012) integrated the pathogenic
and salutogenic approaches represented in 17 definitions and 12 models of
health literacy. The authors described three domains of health literacy focused
on disease treatment, disease prevention (both pathogenic) and health promotion
Maternal Health Literacy Crosses
A mother uses health literacy skills
to function in each of these domains. She functions in the healthcare system
when she is an out-patient in prenatal care or oral healthcare, when she is an
in-patient in obstetric care, and when she obtains health services for her
child. She functions in the prevention domain when she engages in preventive parenting practices (e.g.
using a car seat) and avoids risky behaviors (e.g. smoking). In the health
promotion domain, a health literate mother engages in self-care practices (e.g.
exercise) and actively supports healthy child development (e.g. reads to the
child). This integrated model is
potentially a giant leap for health literacy research. Stay tuned.
T, Chen E & Bennett H. (2009). Confronting the Growing Burden of Chronic
Disease: Can the US Health Care Workforce Do the Job? Health Affairs 28 (1).
65-74. Available online:
K, Van den Broucke S, Fullam J, Doyle G, Pelikan J, et. al. (2012). Health
Literacy and Public Health: A systematic review and integration of definitions
and models. BMC Public Health12:80
. Available online: www.biomedcentral.com/1471-2458/12/80.
M. (2013). Health Literacy: An Opinionated Perspective. American Journal of
Preventive Medicine 45,e35-e40.
What causes disease?
For 200 years,
Western medicine has worked from the idea that health is the absence of
The overarching question for medicine and healthcare has been What
causes disease? And despite
the name, healthcare has always been about treating disease. Early on, care and
on germs and infectious disease; later , following the
research, focus shifted to genes and risk factors
for chronic disease. Although
it is now widely accepted that health is more than the absence of
disease, Public Health, and even the relatively
new field of Health Promotion, still maintain a steady
focus on reducing
disease risk factors. It’s time for a new question.
Prerequisite for Health:
- Stable eco-system
- Sustainable resources
- Social justice
Research has answered, in broad terms, the centuries old
The roots of disease grow deeper and earlier than germs or genes and
risky lifestyles. It is
well-established that health and disease originate in early development, in the
“zero to three”, prenatal to preschool period. The
combination of Nature (genes & germs) and nurture (early parenting and
environment) in the earliest months and years of life establish the foundation
for all that follows: how
susceptible we are to disease, how resilient we are,
and further, how we learn, make friends, cope with challenges,
what we want.
Research breakthroughs have
given health a new broader meaning that is
expressed and accepted more internationally than in the US.
It is now clear that health and disease originate in early
development; and that health, like disease,
develops over time and its
trajectory can be influenced, especially during fetal and early child
development and other critical periods of development. That
understanding demands that we flip
the overarching question to ask, What
causes health? And to flip the concentration of resources from
end of life
care to maternal and child health promotion.
What causes health literacy?
Most health literacy research has taken place in US academic
medical centers under the old overarching
question asking, What is the role
of low literacy in disease? It is important to note that this research
also uses an
outdated understanding of literacy as reading ability. This line of research
that few Americans understand medical terminology and nearly
all of us have difficulty following complex
medication regimens and navigating
the complexities of healthcare and insurance.
If we start with the new overarching question: What causes
health?, then a more actionable
literacy promotion is What will empower this person to use
information and services for health?
The answer, that which empowers a person to use information and
services for health, is health literacy.
Better information is necessary, but rarely
sufficient. Look to the Prerequisites for Health (above) to see
other factors necessary to develop health and health literacy.
Antonovsky A. (1996). The salutogenic model as a theory to guide health
promotion Health Promotion
International 11 (1);11-18
Halfon N, Larson K, Lu M, Tullis E
& Russ S. (2014). Lifecourse Health Development: Past, Present and Future.
Child Health Journal 18:344-365.
D. (2008). The evolving concept of health literacy. Social Science &
Medicine, 67, 2072-2078.
Shonkoff, J. P.,
& Phillips, D. (2000). From neurons to neighbourhoods. The Science of
Development,: National Academy Press: Washington DC.
Today I am sending love and light and courage to all mothers of
black sons; their hearts must be in their throats. Every day. All day. But
especially today. Because racism
in America is so not not a thing of the past.
The American justice system has again declared that its okay for
an adult white man with a gun to kill an unarmed black teenager because the
adult is afraid. It is one
highly questionable shocking thing for an untrained, self-appointed vigilante
alone in the dark to claim a level of fear that justifies killing - and have
the courts uphold that claim. The Ferguson incident is something different, more frightening, dangerous
I don’t know what happened in Ferguson. But one must question how a trained
police officer, pledged to protect citizens, inside his vehicle with a gun and
backup on the way, facing a
teenager with only cigarillos in his hand, whose crimes are lifting a handful of tobacco products from
a convenience store and walking in the street — how can that officer be so
afraid and so without options that he must shoot to kill. Multiple times.
Before backup arrives.
We have to ask, why are the Ferguson police so afraid of those it
is their duty to protect? Do they
receive no training in race relations, or conflict resolution, in take down and
control, in any form of self-defense that does not rely on lethal weapons?
Racism is fear of someone who does not look like you. Fear as a legal justification for police
shooting down citizens in the streets institutionalizes racism. Fear as
justification for transforming a grand jury into a secret trial for the killer
further institutionalizes the racial divide.
Divided we fall. A people living in fear of each other cannot
achieve optimum health, or high productivity, or spiritual advancement, and
certainly not liberty and justice for all.
My hope lies with the mothers and fathers and spiritual leaders
in Ferguson and across America who call upon themselves, their sons and their neighbors —yet
again— to be the ones to demonstrate restraint under pressure, to
practice non-reaction when provoked, to keep thinking in the face of fear, to live up to being an American. Stay strong, Mothers.
The third era of healthcare
It started in the 1980s.
Epidemiologists —they study how disease is distributed
realized that events and experiences we
have in the womb —before we are even born—influence
our health in middle age. Discovery of the “Developmental Origins of Health and Disease (DOHAD)
what they mean by landmark research; it marks a turn that requires a new way of
and measuring health, and a second transformation of healthcare
Halfon and colleagues trace the
evolution of healthcare from the first era —1900-1950—
when medical and health systems focused on germ theory
and acute care of infectious disease.
Around 1950, gene theory and social research led to bio-behavioral
theories that said disease
results from the interaction of genetic make-up and
adult health behaviors. So the
era of healthcare refocused thinking and resources on chronic disease.
tried in vain to change adults’ risky behaviors. Later researchers recognized that gene
networks interact with each other and the environment in complex and dynamic
influence how our bodies and minds are engineered and re-engineered
to function in our
environments. This is when we started talking about the
social determinants of health.
By 2000, the synthesis of
biological, behavioural and social sciences led to the slowly emerging
era of healthcare where your doctor will focus less on chronic disease
diagnosis and treatment
on lifecourse health development.
The goal of Medicine will be to optimize your health
trajectory — the way your health plays out across your lifecourse,
from preconception through infancy,
childhood and on to old age.
Thought leaders now are talking
about health as a capacity—an ability or power to
of do something.
Health is used to achieve one’s
potential and accomplish one’s goals.
Clarifying the Health-Literacy Link
to achieve ones potential and accomplish one’s
goals, to function in some social context. In other
words, you’re healthy and literate when you function — interact successfully— with
We could say further, you are health literate when you
interact with your environment in ways that
optimize your health.
Context Matters. Embrace
Transition to the third era of
health care requires refocusing heath literacy research and practice on
environment in which health and disease develop, that is, on the context in
which people make
information and use it for health and healthcare decision making and
goal of health
literacy promotion for the third-era is to optimize a person’s or a community’s
trajectory. That means we need to be promoting maternal health literacy
Repositioning Maternal-child Heath
Further, the rapidly increasing
understanding of DOHAD —the developmental origins of
disease— positions maternal-child
health at the foundation of personal and public health and at the
center of an evolved third-era
healthcare system. It makes maternal health literacy the foundation
why I am working on ways to use data to understand the contexts in which
health and maternal health literacy develop. Successful efforts to untangle the web
that influence the health trajectories of a mother and
her child may answer the health literacy
essential question: Where to begin?
Halfon N, Larson K, Lu M, Tullis E
& Russ S. (2014). Lifecourse Health Development: Past, Present
and Future. Maternal
Child Health Journal 18:344-365.
Start with measurement
What we measure and how we measure it
matters because it determines what we
find out about what works and what’s
worth doing and who should do it.* Measurement
remains the most crucial issue
for health literacy research
; because we need to find
out what works for
whom, and what’s
worth doing and who should do it.
especially interested in what works for mothers in
the prenatal to preschool
healthy population. What mothers learn about health and
during pregnancy and early parenting can benefit entire families
across their lifespans,
and extend benefits to the healthcare, education and
justice systems, and to the economy.
Health literacy focuses on patients
understanding healthcare information
Health literacy research assesses
literacy by their scores on a single
administration of a reading test using
medical terms. Patients are marked poor, marginal
or adequate. An
adequate score means you will probably not need assistance to make
information about your diagnosis
or to follow treatment instructions.
you cannot pronounce most of the words, you are assumed to have poor health literacy
and to be
unable to “obtain,
process and understand basic information needed to make
What we find out from health
literacy-reading test scores is that almost everybody has
vocabulary and difficulty making sense of information from the healthcare
system. We find out that information needs to be simplified and its delivery
needs to be
improved. We find that patients score better when we give them
better information and
conclude that what’s
worth doing is improving information and its delivery. Since most
studies originate in
academic medical centers, it is not surprising that studies position health
professionals as the keepers and dispensers of health and medical knowledge and
so it falls
to them to reduce the risk and mitigate the negative impacts of low
[health] literacy on
patients and the system.
Maternal health literacy focuses on
parents using information for health
Maternal health literacy research
assesses periodically what parents do with information,
how they integrate it
into their lives and households. Changes in parent’s
healthcare-related actions, practices and behaviors provide
evidence of progress (or
regression) in developing the knowledge and social and
cognitive skills needed to participate
in healthcare and preventive practices.
This approach captures effects of systems efforts to
improve information as
well as public health efforts to directly assist parents to make meaning
the information and apply it in real life.
By monitoring what parents actually
do for health with the information available to them, we
find out that direct
assistance to use information and services for health is most beneficial to
lower functioning parents, while also benefitting higher functioning parents.
We find that social
workers, parent educators, health educators, and trained
paraprofessionals working in homes
and communities can enable parents to better
manage family health and healthcare, even with
the added challenges of poverty,
limited education and limited English proficiency.
Both approaches are needed
The dominant clinical approach to
literacy and the public health approach to
maternal health literacy are
complementary rather than exclusive. Patients and parents need
information, accessible services, and assistance to use them effectively.
schorr Common Purpose: Strengthening Families and Neighborhoods to Rebuild
Read this book!
The morning was chilly, definitely
fall in the air. I turned on the
furnace. It seemed to take a while
but the house warmed up. Just as I
noticed my nose was no longer cold, a
contractor doing repairs on the exterior reported with some alarm the
smell of gas around the furnace exhaust. I turned off the heat. Two days later
the scene repeated itself. The previous residents could not recall any problem
with the furnace, or ever having
I called a local heating company.
The tech walked in the door,
sniffed the air, and immediately pulled out his hand-held CO - carbon monoxide
- monitor. His eyebrows went up.
He ordered all the windows and doors opened. Then he went outside to get a reading at the exhaust vent.
He left the area when the reading got to 260 - more than 10x the standard.
What you don’t know can hurt you
Would this explain my headache
that won’t go away, I asked. Yes. And dizziness, drowsiness or
a lightheaded sort of flu-like feeling - early signs of carbon monoxide
poisoning. That’s what kills a person who sits too long in a car in
the garage with the motor running.
Turns out the furnace heat
exchangers - whatever those are - had cracked, probably years earlier causing
the furnace to leak moisture and over heat. It had been deteriorating,
gradually producing less and less heat with more and more gas.
never thought about the furnace beyond the thermostat. I took for
granted that it protected my health by providing heat in the winter. It never occurred to me that it could be
Use information and services in
ways that enhance health.
the definition of health literacy. With many households switching to affordable
gas heating and appliances, keeping healthy requires new awareness. Here’s information I learned about maintaining gas
appliances that you, and families you serve, can use to protect and enhance
health this winter.
Get a CO
monitor. If you have any gas
appliances get a monitor. Building codes now squire them in new construction.
If you have a gas furnace put one in each bedroom. I got a model that’s
guaranteed for 10 years for $23 at WallMart. It plugs in to any outlet. The
alarm sounds if the CO level reaches 70 ppm -parts per million - the
point when most people start to feel symptoms. For a little more money you can get a monitor that shows the
ppm . For a bit less, there are battery powered monitors, but you have to
monitor the battery.
If the alarm sounds, get to fresh
air and call 911.
furnace checked annually- a great way
to mark Health Literacy Month each October. The local heating company charges
$109 to check the system including the ducts. The new furnace I bought cost
$4500. If the furnace had been checked annually for the last 20 year that would
have cost a total of $2180.
filter every six months. My local
heating company provides free filters and will change them at no charge 2x a
year. Does yours?
smell gas, do not ignore it. Turn off the appliance. Open doors and windows. Call
for service to the appliance. Do not wait for the alarm to sound.
numbers. CO level at the furnace’s exterior exhaust should be < 24ppm (parts
per million). The level in front
of a gas fireplace should be < 9ppm. My fireplace tested at 30ppm. It is off. It will be
Social media and the NFL are enabling us to
reflect together on what level of aggression and violence in family
relationships is acceptable in our society. It's a fitting although
inadvertent role for the NFL, whose players are de facto role models for
American males, and whose recruiters, coaches and fans place high value on
aggression and violence on the field. (Here is Seattle, we love the defense in
Beast Mode - on the field.) The NFL's position on aggression at home is, well, evolving.
Thanks to the inventors and users of social media.
There seems to be consensus that child
abuse is unacceptable, and discipline is necessary. But the line between
discipline and abuse is defined by a complex and dynamic web of personal
beliefs, local culture, and state laws.
What is abuse?
It depends who you ask and where you are. State law
is largely focused on protecting parents' rights, and keeping the family free
of government or social interference. Social workers focus on protecting the
child from parental excess. The courts aim to balance parents' rights with
children's welfare. There's controversy regarding how much weight should be
given to potential effects on children's social and emotional wellbeing and
healthy development, on what is "normal" in the child's community, on
potential future harm, on how well the punishment fits the infraction, on a
pattern of parental behavior.
State laws are intentionally vague about what
constitutes abuse, so that cases can be decided on an individual basis.
The laws and their approaches to defining abuse vary widely. Interpretation on
the ground varies by agencies and individuals. This can result in a "I
know it when I see it" understanding of child abuse. Judging by the
Twitter traffic around Adrian Peterson, people who view the same video evidence
interpret it very differently.
How to decide?
Ultimately, parents must decide whether, when
and how to discipline their child. To me there are two important things to
bring to mind when discipline is in order. First, every young child wants to
be, tries to be like his or her parents. And every parental action teaches the
child some lesson, by default or by design.
A clear distinction for me is that disciple
is teaching by design.
It intends to teach the child appropriate behavior
and right action. Abuse is teaching by default, it aims to punish inappropriate
behavior. As a parent, the question to ask when provoked by a preschooler, or
any child, is what do I want to teach now?
Adrian Peterson said he wanted to teach his son
to be respectful and not curse at playmates. But his preschooler did not make
up those swear words. He learned them from someone he is trying to be like. And
hitting a person with a stick is about as disrespectful as one can get.
Peterson left a scar on his 4-year-old's head, which he said the child
could have avoided by not trying to get away. Would you try to get away
from a brawny footballer coming after you with a stick? I sure would. Would you
think he was abusing you or that he was teaching you appropriate social
Consider what that boy is going to say to
himself as he grows up looking in the mirror at his scar? "I want to
be respectful and polite like my dad". Probably not.
This from Beginnings Parents Guide
Translating research into practice is a challenge for all practitioners. We could call
literacy” - ability to obtain, understand, evaluate and use research to make
treatment and policy decisions. How can clinician/educators of healthcare
professionals enable new clinicians to use research to challenge current
practice and provide evidence-based care? How do you implement changes to long
standing curricula, evaluation procedures, and teaching methods? How do you
capture the richness of diversity and overcome its challenges? Those are
questions faculty, staff and students of University of Cape Town School of
Nursing have been actively wrestling with in recent years. The questions guide
their research which is “relevant to and directly transferable to local and
resource-constrained practice settings”.
Learnings to be published soon
I know this because I am guest-editing a special
edition the African nursing journal Curationis.
This work, like the special edition itself, is an outgrowth of one of my all-time
favorite gigs - keynoting the first, totally awesome and inspiring, conference
on Building Children’s Nursing for Africa
April,2013. (Consider participating in the second conference April 22-24,
So I get to read all
the articles and shepherd them through the publication process. What an
education i am getting! The issue
is shaping up nicely. I think it is going to valuable to all nursing and
medical educators working with diverse student bodies or training professionals
to serve low-resource populations.