Menu ENN Search
Language: English Fran├žais

Cause-effect

This question was posted the Infant and young child feeding interventions forum area and has 7 replies.

» Post a reply

Halima S Hillow

Nutrition project manager /World Concern

Normal user

10 Oct 2015, 08:37

Can the results obtained from a smart survey be used for cause effect esp. in IYCF section after comparison with baseline ? We had implemented a program in BCC using care group model and wanted to evaluate after a year to see if we have made any progress so far. The major issue is we cover all aspects of BCC in health and nutrition and not specifically IYCF. Thanks

Bradley A. Woodruff

Self-employed

Frequent user

10 Oct 2015, 18:32

Dear Ms. Hillow:

You ask a short question which raises very complicated issues. Philosophers have been pondering the nature of causality and the evidence thereof for hundreds of years.

The short answer is no, data from a cross-sectional population-based surveys cannot provide strong evidence of causality. You are measuring characteristics of a population, and populations are subject to notoriously complicated influences. If you find a change after implementing some program, there may be, and probably are, many other things which could have produced the observed change or inhibited the observed change.

Evidence for causation can be strengthened by having a control group, or in this case, a control population, as similar as possible to the intervention population but not receiving the intervention. Control populations are best used by measuring the outcomes of interest at baseline in both the control and intervention populations, then measuring the same outcomes using the same methodology in the control and intervention populations at some time after the intervention is implemented. If the change is greater in the intervention population than in the control population, this change may have been due, at least in part, to your intervention.

However, this is a very simplified summary of a complex issue. A better summary of the larger epistemologic issues can be found here: http://jech.bmj.com/content/56/2/119.full. In addition, any introductory epidemiology textbook will discuss the criteria to demonstrate causality in epidemiologic studies, and other books give excellent advice on use of community studies to evaluate public health programs.

Halima S Hillow

Nutrition project manager /World Concern

Normal user

11 Oct 2015, 04:52

Hi Brad ,
Thanks for your reply,yeah i do remember epidemiology and the causality factor. In my instance it would be difficult to have a control population and it will be ethically wrong for me to do that .
Is there any other specific way to address this ,for example i have been following up on breastfeeding within 1 hour for the last 6 months(after training and putting more efforts ) and maybe i realize there is a difference in current survey compared to the baseline . How do i report if there is any difference. Can i say the training's had effect or ?
Thanks

Anonymous 81

Public Health Nutritionist

Normal user

11 Oct 2015, 05:23

In such condition, when there is no control or comparable group at baseline, I think you can do similar survey in neighboring communities, outside your area of intervention. However, you have to make sure both communities are homogeneous or share similar characteristics. the assumption here is that the two communities are similar except your program. By comparing both results you can assess the added value of your intervention.

Bradley A. Woodruff

Self-employed

Frequent user

11 Oct 2015, 16:22

Dear Ms. Hillow:

As long as you have only baseline and follow-up measurements of indicators, I don't think you have strong evidence that any change in the indicators is due to your program.

Jo Anne Bennett

Normal user

11 Oct 2015, 16:42

Consider that it may not necessarily be important for program-related decisionmaking to say that the condition is "due to" your program. The more information you have about pre-program conditions and the more measurement points you have for these conditions after your program started, the better. And of course, pay attention to collateral conditions and changes therein (i.e., what else was going on). In other words, the composite of information, quantitative and qualitative, is key to observing progress toward goals. Program evaluation is not the evaluation of an experiment or hypothesis testing. Causality isn't the issue.

Dr Marko Kerac

Course Director, Global Nutrition MSc, LSHTM

Frequent user

11 Oct 2015, 17:12

Is it causal? Considering the BRADFORD-HILL criteria:

Whilst of course properly designed and executed intervention studies are ideal in helping us decide whether things as causally related or not, there are many situations in which this is not possible / practical / ethical. Hence it's important to make the best of observational data. In addition to approaches already listed by other respondents, I've always found it helpful to go through the "Bradford Hill" criteria to establish whether something is more likely causally or more likely non-causally associated:

See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1291382/ for a good summary (and critique) which discusses in more details the key points below:

"1) Strength of association
- A strong association is more likely to have a causal component than is a modest association

2) Consistency
- a relationship is observed repeatedly

3) Specificity
- a factor influences specifically a particular outcome or population

4) Temporality
The factor must precede the outcome it is assumed to affect

5) Biological gradient
The outcome increases monotonically with increasing dose of exposure or according to a function predicted by a substantive theory

6) Plausibility
The observed association can be plausibly explained by substantive matter (e.g. biological) explanations

7) Coherence
A causal conclusion should not fundamentally contradict present substantive knowledge

8) Experiment
Causation is more likely if evidence is based on randomised experiments

9) Analogy
For analogous exposures and outcomes an effect has already been shown


Hope that helps.

Halima S Hillow

Nutrition project manager /World Concern

Normal user

11 Oct 2015, 17:44

Hi everyone. Your comments have been helpful and probably will not use causality but the data for just as program evaluation. I understand causality is the complicated way to look at any change in a program as many factors either known or unknown may have contributed to it.
Much appreciation .

If you have any problem posting a response, please contact the moderator at post@en-net.org.

Back to top

» Post a reply