Critique of Study: More BSNs equal better pt outcomes

Nurses General Nursing

Published

This is EXTREMELY long but worthwhile to read if the topic interests you.

Linda Aiken et. al., in 2003 released through the JAMA a landmark Study, "Educational Levels of Hospital Nurses and Surgical Patient Mortality"

The study is oft cited and contends that evidence suggests that higher rates of BSN education at the bedside directly translates to improved pt outcomes.

This is my critique:

Why the study, "Educational Levels of Hospital Nurses and Surgical Patient Mortality" is flawed.

1. Academic Laziness

The original data pool was used for an earlier study about staffing levels and mortality GENERALLY. That data was just copied onto this template for this study. But it wasn't just copied; it was copied with the full assurance of the authors that the results of the first study that used this data could be 'factored out' of this, subsequent study.

2. Discrimination Bias (Hospital Selection)

Before analyzing the data, the authors first decided that it would be necessary to 'exclude' hospitals that didn't fit their data set. Some were excluded for valid reasons (they didn't report to the data set. Although, however valid, the exclusion ITSELF taints the data. THIS IS EXPECIALLY TRUE SINCE THIS EXCLUSION INCLUDES ALL VA HOSPITALS - a known source for high BSN recruitment. The very hospitals that might yield some useful data on the subject were ELIMINATED from the study!) - but some were excluded because the data they generated didn't meet the authors' needs. In other words, INCLUSION of said data would disturb the conclusions of the study.

So the authors warrant that exclusion of some data is relevant. Ok, I can concede that point as I understand that large standard deviation multiples (outlying data) can skew the majority of data. But, excluding large amounts of data that are quite possibly within a single standard deviation of what is being studied on the basis that such data wasn't available serves the purpose of undermining the whole study. It is a frank admission that the data itself is incomplete, and so, suspect.

This is the compounded error of the academic laziness mentioned above. The data set was copied from another study with the full understanding that it didn't meet the needs of this study, AND COULD NOT MEET THE NEEDS OF THIS STUDY because of its lack of inclusion of hospitals MOST LIKELY to represent a significant sample of this study. Rather than develop data that was 'pertinent' to THIS study, that academic laziness now calls for this lacking, and possibly highly relevant, data to merely be excluded from consideration.

3. Degree Bias

The Authors state in the study, "Conventional wisdom" is that nurses' experience is more important than their educational levels." It is this ''conventional wisdom' that the study aims to examine. But how does it do so? By buying into the exact same conventional wisdom!: "Because there is no evidence that the relative proportions of nurses holding diplomas and associate degrees affect the patient outcomes studied, these two categories of nurses were collapsed into a single category"

HOLD ON. In a study about how degrees affect patient outcomes, an essential tenet of the study is to disregard degrees held??? After such manipulation, how can you say with a straight face that a study that disregards the relationship between degrees can make a conclusion REGARDING the relationships between degrees?

4. Lack of Substantiating Data

"It was later verified that this decision did not bias the result."

This statement, or others like it, appear throughout this 'study' without mention of the methods used to 'verify'.

"Previous empirical work demonstrated. . ." - um, exactly WHAT empirical work was that?

In fact, the study makes lots of claims and manipulates the data in lots of ways that it nevertheless insists that you have to trust its 'independent verification' that such didn't bias the results. Of course, that is without being provided access to said independent verification.

You have to love the 'self-affirming' validity of it all.

5. Data Manipulation

A. The data was 'manipulated' to grant varying degrees of credibility depending upon whether it was received by a 'teaching' hospital vs. a 'non'-teaching hospital.

B. The data was 'manipulated' to grant varying degrees of credibility to hospitals that are more 'technological' (e.g. have transplant services) as opposed to less.

C. "An important potential confounding variable to both clinical judgment and education was the mean number of years of experience working as an RN": telling comment, but never fear, the data was 'manipulated' to take this into account.

D. Nursing workloads might affect patient outcomes. (Indeed, THIS was the previous study that this study's data set was copied from.) But, in this case, the data was 'manipulated' to take those workloads into account.

E. "Estimated and controlled for the risk of having a board certified Surgeon instead of a non-board certified Surgeon." The use of 2 'dummy variables' comparing MD licenses to general vs specialty board certification was "a reasonable way for controlling surgeon qualifications in our models."

In fact the authors admit to manipulating the data 133 ways! But all of these 'manipulations' were later 'verified' to have produced no bias.

6. Key Criteria Conjecture

The study's two key criteria: deaths within 30 days of hospital admissions and deaths within 30 days of complications due to 'failure to rescue'. But how were these criteria established?

In the first case, they were established by comparing the data set to vital statistic records (death records). I doubt they accurately compared 235,000 individual patients (data points) against another data set (death records) that was probably multiple times in size, but OK - I'll buy this for the moment.

In the second case, however, 'failure to rescue' was defined - NOT BY EXAMINING ACTUAL CASES OF FAILURE TO RESCUE - but by establishing different ICD-9 secondary codes from admit to discharge. An assumption is made that a different code meant that a 'failure to rescue' had occurred. What?!

RE-READ THAT LAST! By making dubious assumptions on data sets (hospital reporting statistics) - this study conjectures how this translates to 'failure to rescue' and then makes conclusions based on what this 'failure to rescue' might mean! ALL BY ITSELF, THIS NEGATES THE ENTIRE STUDY.

But, it was 'verified' to not bias the study results. How was this part 'verified'? Well, you're gonna love this: "expert consensus as well as empirical evidence to distinguish complications from pre-existing co-morbidities."

In other words, the experts (the study authors) know which data is valid for purposes of inclusion into the study - and which data isn't. The 'experts' consensus is the key element that ensures non-bias.

There are no 'double blind' studies. No sample populations of RNs. The criteria for inclusion of 'data' is solely based on the 'consensus' of the 'experts' creating the study. And these 'experts': backed by AACN (Amer Assoc of Colleges of Nursing) - An organization committed to BSN-entry and an organization which maintains, on its website, a valiant defense of this study:

http://www.aacn.nche.edu/Media/TalkingPoints2.htm

No, no possibility of bias here.

Let me ask you this: if you know of a study conducted by Republican Pollsters - where they alone determined whose answers were valid - would you trust a result that brags that 'Most Americans Love President Bush!' But here's the question I really want to ask: WHY wouldn't you trust such a result?

7. Risk Adjustment.

Still trust this study? Try this one: "Patient outcomes were risk-adjusted by including 133 variables in our models, including age, sex, whether an admission was a transfer from another hospital, whether it was an emergency admission, a series of 48 variables including surgery type, dummy variables including the presence of 28 chronic, pre-existing conditions as classified by ICD-9 codes, and interaction terms chosen on the basis of their ability to predict mortality and failure to rescue in the current data set."

So the data was manipulated 133 ways, excluding some data. But, and this is key: there are SO VERY MANY variables that could effect patient outcomes that you have to adjust for EVERYTHING except for what you're looking to find. Right? This is not only what the authors contend, but they contend that they SUCCESSFULLY adjusted the data, 133 different ways, for just this purpose, and completely without bias. Amazing.

8. Logistics Regression Models

So, after the study took in all this manipulated 'data', it compared hospitals with higher BSN-RNs to those with less, and reached a conclusion. Right? Wrong.

It took the data and ran a 'logistics regression model' as to what might happen in a given hospital "if there were a 10% increase in BSN RNs."

This study doesn't even compare the relative levels of RN education. Let me repeat that: THIS STUDY DOESN'T EVEN MAKE THE COMPARISONS IT PURPORTS TO HAVE STUDIED. This model and, as a result, this study doesn't compare existing situations. Instead, it makes assumptions regarding potential situations compared to current situations.

Do you get this: the study wasn't designed to test real conditions. The study was designed to create hypothetical situations and comment on the validity of said models based on highly modified and incomplete data.

THIS STUDY SPECIFICALLY COMMENTS ONLY ON HYPOTHETICAL SITUATIONS. Study Disclaimer: ANY RELATIONSHIP TO REAL CONDITIONS IS ONLY IMPLIED BY THE AUTHORS.

Now, see if this isn't a key statement: "The associations of educational compositions, staffing, experience of nurses, and surgeon board certifications with patient outcomes were computed before and after controlling for patient characteristics and hospital characteristics." Indeed.

9. Direct Standardization Models.

Apparently, even after all the above manipulation, there were still 'clusters of data' that had to be 'standardized' using 'robust estimations'. The study does at least have the guts to admit that such 'standardizations' turns the final conclusion into an 'estimation'. Too bad it only makes that admission in the body of the study, and not in the 'abstracts'.

10. Alternative Correlations

The study admits that fewer than 11% of hospitals in Penn in 1999 (the area/year of the study) had 50% or greater BSNs (Excluding the VA hospital system, which were completely ignored by the study.) And then the study cites co-factors that could unduly influence the study under these situations: "Hospitals with higher percentages of BSN or masters prepared nurses tended to be larger and have post-graduate medical training programs, as well as high-tech facilities. These hospitals also had slightly less experienced nurses on average AND SIGNIFICANTLY LOWER MEAN WORKLOADS (emphasis mine). The strong associations between the educational composition of hospitals and other hospital characteristics, including workloads, makes clear the need to control for these latter characteristics in estimating the effects of nurse education on patient mortality."

Wow. Two key things from that statement: a direct acknowledgment that this 'study' is an 'estimation' and an acknowledgment that such an 'estimation' only occurred after 'the need' to highly manipulate the data.

In fact, I think it much more likely to argue that such "co-correlations" makes any 'estimated' conclusions IMPOSSIBLE to verify.

11. Study Conclusions.

This is one of the study's least reported conclusions. See if you agree: "Nurses' years of experience were not found to be a significant predictor of mortality or failure to rescue in the full models." Re-read that and UNDERSTAND the implications of what it means.

The authors admit that their "estimations" can only lead to an "implication" that increased education means better nurses. OK. I'll agree with that. But, because the same study 'factored out' experience, I think it is impossible to estimate how even a fraction of experience affects the conclusions of the study.

Indeed, in order to arrive at its conclusion, the authors must first dismiss the 'conventional wisdom' that experience IS a factor, as they did, in the above statement. Without the above assumption, this whole body of work is worthless. If experience factors in, then the key question cannot be tied simply to education, BUT MUST BE TIED TO BOTH QUALITIES.

And so, the authors find themselves in a conundrum, in which they must first dismiss the importance of experience in order to highlight the importance of education. Amazingly enough, their study reached both conclusions: experience is meaningless to patient outcomes and THEREFORE education level is, by itself, a measurable standard.

The problem with that is, once experience is dismissed, the correlation between education, experience, and patient outcomes is NOT part of this study. Even if you COULD credibly claim that there is no correlation between experience and outcomes (a silly claim), once you add education level into the consideration, you create a new dynamic. By dismissing experience from the equation the study also dimisses its own results, which NOW have the effect of ascribing the results and effects of a real-life system (education AND experience vs outcomes) to a completely different and hypothetical system (education alone vs outcomes).

In short, the claim that experience is not a factor and can be excluded from the study of education's impact on quality is the equivalent of stating that nature is not a factor and can be isolated from nurture in the study of human behavior. In truth, the concepts are much too intricately linked for bland assurances of non-bias in the elimination of part of either equation.

Also not taken into consideration is alternative educational pathways, such as non-BSN bach degree'd RNs (To include both Accel Programs and '2nd Career' ADN nurses.)

The study also fails to note that many BSNs are prior ADN students. While the subset of BSN included ADN graduates, the subset of ADN graduates ALMOST NEVER includes BSN graduates. This would obviously skew the data unless this characteristic were isolated from the data set. In fact, the data set isn't a pool of RNs but pt discharge records and there is no way included within this study to make a distinction.

Given the broad range of said experiences and educations within nursing, negating those experiences and educational pathways also serves the purpose of negating the validity of the study itself.

My conclusion:

Saying that education is a bigger factor than experience in ANYTHING is the same as saying that nurture is a bigger factor than nature in ANYTHING. The relationships are so intricately linked as to be inseparable. As a result, these types of arguments rise to the level of philosophy.

This study claims the ability to make such distinctions, using incomplete and highly manipulated (133 ways by its own admission) data and applying that data only to hypothetical situations.

This is not science; it's propaganda.

Simply put, this flawed and un-reproducible study is worthless as anything BUT propaganda. And that's the bottom line.

~faith,

Timothy.

I wasn't aware that I needed to 'google' my opinion. Darn that independent thinking!

Specializes in Too many to list.
Fascinating thread. And it touches upon an aspect of nursing I've wanted to ask for ages but never found the right opportunity to do so.

If this question really detracts from the thread, please feel free to ignore it.

My question:

My Father has often told me that this whole business of graduating from school and then having to pay someone to sit for the NCLEX so that the State can grant you a 'professional' lisence - then having to go to a job and undergo orientation/training anyways makes no sense. He says that the whole lisencing process as it stands today is BS - just another way for the State and/or the 'professiona' bodies to make more money by selling the bunkum that some lisence is required by taking a particular exam and that this is somehow more required that that initial orientation/training.

Is he mistaken? Is there some grain of truth to this?

Thanks

Just an aside from this thread:

Maybe your dad is right. Many libertarians feel this way about state licenses including marriage licenses, car registrations, driver's licenses etc.

It is like living in an alternate reality. It can be done, but it's really, really difficult. The Amish are doing a version of it.

Thank you all for your opinions. Timothy did an excellent critique.

When I read the original study in JAMA it rang true.

The second study disturbed me. The logical conclusions of the first were absent in the second.

I didn't bother to analize why. Was I lacking in logic or research skills? After all i dropped out of grad school.

Clearly the ability to assess and prevent a crisis is a combination of education and experience.

This is a great subject.

Specializes in Long Term Care.

I have an idea for a study design.

Let's have ONLY six units of Nurses participate in a year long study.

Unit One: All ADNs with less than Five years experience.

Unit Two: All BSNs with less than Five years experience.

Unit Three: All ADNs with more than five but less than thirty years experience.

Unit Four: All BSNs with more than five but less than thrity years experience.

Unit Five: MIX of ADN and BSNs with MIXED levels of experience.

Unit Six: Control (can anyone think of what a control group might look like?)

We would look at specific criteria similar to the ones used in the study.

The six units would have identical policies and procedures that all the nurses participating in the study would be inserviced on.

The kinds of clients being admitted to our units would be general med-surg patients.

Hmmm I am fading I have to go think about this a little longer.

Specializes in Critical Care.

A recap on why the Aiken study regarding mortality and education is seriously flawed:

1. Significant Data Ignored

The authors used the data they had gathered for their previous study, on mortality vs patient ratios. It was not a good fit for this new study, and as a result this study left out military and VA hospitals, and small hospitals. In other words, the hospitals MOST likely to have high and low percentages of BSNs were left out of a study regarding the effects of BSN on care. You cannot just ignore significant population segments within a study and then claim that your observations could apply generally to the population.

For example, if I were studying speeding as a relationship to vehicles that people drive, and I left all sports cars out of the study because my data didn't include information on sports cars - and then I came to the conclusion that most drivers do not speed in their vehicles - how accurate would that study be?

2. Degree Bias

Imagine just how monumental this study should be: is there a difference in outcomes between degrees? Now, look at THIS statement, in the body of the study: "Because there is no evidence that the relative proportions of nurses holding diplomas and associate degrees affect the patient outcomes studied, these two categories of nurses were collapsed into a single category."

Hold on there for just a second! There are two very important things about this above statement.

First, how can the authors blithely dismiss the potential differences between ADN and Diploma degrees in a study about the differences between degrees? What methodology did they use to reach this conclusion? Wouldn’t such a finding merit AT LEAST AS MUCH attn as the study itself? Isn’t there a high level of hubris involved in dismissing the differences between ADN and Diploma in a study about the comparative value of degrees?

Second, what this means is that the authors simply didn’t study BSN vs. ADN, or BSN vs. Diploma. By themselves, maybe ADN degrees would outperform BSN. Or maybe, Diploma would. Or maybe, both degrees would outperform BSN, if measured individually. We’ll never know, as it wasn’t a part of this study.

3. Author Bias

Instead of examining real life situations, the authors looked at ICD-9 codes on State reporting records from hospitals in Penn in 1999. They compared these to death records. If there was a death AND a subsequent ICD-9 code (a code entered after the original, admission code(s)), then the authors determined if this was a new event, a 'failure to rescue', or a "co-morbidity". The authors, “in their own expertise”, decided which of the subsequent ICD-9 codes that they examined equated to ‘failure to rescue’ and which were 'co-morbidities'. Any event they deemed 'co-morbidity' was eliminated from further consideration, as they were looking for events deemed to be, 'failure to rescue'.

In the real world of science, for a study to be valid, there must be some level of ‘double-blindness’. There must be a separation between the data that goes in and the results it produces. Otherwise, if you were so inclined, you could just manipulate the data going into a study until the results become what you want. It’s the old cliché, ‘garbage in, garbage out’.

Manipulating the data that went into the study is JUST what the authors did. IN THEIR EXPERTISE, they sorted which data made it into the study, and which data didn’t. It doesn't matter if they were intellectually honest, or not. It is the POTENTIAL for abuse here that completely undermines this study.

Now, do you think it matters that this study was funded by the AACN – an organization known to strongly promote BSN-entry education of nurses? Why would this be important? Am I just shooting the messenger here? In logical fallacy terms, am I simply engaging in an ad hominem attack?

If I’m a pollster and I produce a poll that includes only the data that I see fit to include, and excludes all other data, and my poll results show that 'America loves Hillary', do you think it would be important to also know that her campaign paid for my polling? More importantly, how would you think knowing my sponsor and knowing that I manipulated the data that went into the study could affect my credibility? Exactly.

Or maybe, it's just a happy coincidence that a study not disciplined by objective scientific controls happened to EXACTLY match the opinions of the backers of the study. It is BECAUSE the authors subjectively sorted the data prior to inclusion into their statistical models that it becomes important to know if they have a particular stake in the outcome. At least their backers got their money's worth.

Or maybe, real science is much more stringent in protecting against the potential of such biases. MAYBE. . .

4. Multi-variable Regressions and Collinearity

You might think that the study compared hospitals with higher numbers of BSNs against those with lessor percentages. You’d be wrong. After manipulating the data 133 different ways, the authors used a ‘logistics regression model’ to examine education – and only education – as a factor in mortality, and then projected that factor into hypothetical situations with hypothetically higher and lower percentages of BSNs.

Sorry, but this is fundamentally impossible. Let me explain why.

First, multi-variable regression studies are limited by increasing the number of factors you attempt to distinguish between. The higher the number of independent variables, the less reliable the results become. In addition, there is a significant issue of collinearity: factors too close to be distinguished from each other invalidate any attempt to segregate them for the purposes of study.

Let’s take multi-variable regression first. Steven Levitt, in his book, Freakonomics, gives a wonderful explanation of logistics regression models. Imagine a bank of switches in which one master switch turns on a light, and a whole bank of other switches are left in the ‘on’ position. If you want to know which switch (or switches), like the master switch, could also turn on the light, then you have to – one by one – turn off all switches but the one you wish to test. Logistics regression is about just that: turning off all other switches, or, accounting for all other possible explanations for why a thing happens – except the one you want to study.

As it turns out, the authors of the study noted 133 ways in which other factors might affect mortality besides education alone. Then, the authors suggest that they turned off all those switches except the one – education. The problem is that the more variables you introduce, the more likely even very small miscalculations could ultimately have exponential affects on the outcome.

How do you determine the difference in education, and education alone, between Fred, an ADN RN in a county hospital with 8 patients, and Sally, a BSN in a city teaching hospital, with 4 patients? How? You use a regression model to eliminate all those differences except education. Except, the more 'risk adjustments' that must be made to equalize these situations, the more likely for error to be introduced.

It is just impossible to suggest that the authors accurately accounted for 133 different variables and were able to switch them all ‘off’ in sync. This however, also gives the authors a different way to manipulate the outcome of the study. Tweaking any of those different variables (risk adjustments) this way or that, by even a small amount, once compounded 133 ways, could produce changes in the results in the lines of orders of magnitude.

This violation of methodology is referred to as overfitting a statistical model.

Then there is the factor of collinearity. In order to perform a regression model, different situations cannot be similar; they cannot lie on the same line, or be collinear to each other. The problem here is that education and experience are essentially collinear. In fact, it is accurate to say that experience itself IS a form of education.

The only way to conduct a study that would note differences in education absent the effect of experience is to eliminate experience as a factor, altogether. Amazingly, this is JUST what the authors found. From the study, “Nurses' years of experience were not found to be a significant predictor of mortality or failure to rescue in the full models.” Re-read that and UNDERSTAND the implications of what it means. Wouldn’t you think that, if the authors truly discovered, as a result of this study, that experience has no impact on mortality, that this fact would be MORE IMPORTANT than the object of the study itself????? Who knew that, on average, a nurse with 3 weeks experience is just as safe in practice as a nurse with 30 years experience?! Well apparently, the authors of the Aiken study knew it.

Can you see how the conclusion that experience is not a factor in mortality is a necessary construct to eliminate the collinearity problems presented in trying to evaluate education alone? More to the point, can you see how this "discovery", that there is no relationship between experience and mortality, simply fails to pass the smell test? Do you believe it? If the authors truly discovered that experience is not a factor in mortality, THAT would have merited mention, high in the abstract and in the headlines this study made. If however, this is just a necessary construct to justify using a regression model, then it would be buried in the small print, which, it was.

Amazing that such a concession, a necessary concession to use a regression model in this study, is also just the concession these authors discovered! Just one thing: it would have been very nice to have available the methodology of how they reached this epochal discovery. I have to tell you, the potential discovery that experience is irrelevant in nursing BLOWS AWAY the conclusions the authors reached, at least by comparison.

5. Standardization

Even after all this, the results didn’t ‘fit’ with ‘clusters of data’ that had to be run through direct standardization models. In other words, the sky wasn’t green like the study suggested, so the study needed a filter. The authors admit, in the small print, deep in the study, that in order to standardize the data, they had to use 'robust estimations'.

'Robust estimations'?! I’m sorry, that’s like saying that except for the fact that she’s had sex, this girl is a virgin! I estimate that this study is wrong. In that, since I am only estimating, maybe even 'robustly', I stand on equal scientific footing and I am being at least as scientifically valid as the study, itself.

6 My Conclusion

Saying that education is a bigger factor than experience in ANYTHING is the same as saying that nurture is a bigger factor than nature in ANYTHING. The relationships are so intricately linked as to be inseparable. As a result, these types of arguments rise to the level of philosophy.

This study claims the ability to make such distinctions, using incomplete and highly manipulated (133 ways by its own admission) data and applying that data only to hypothetical situations.

This is not science; it's propaganda.

Simply put, this flawed and un-reproducible study is worthless as anything BUT propaganda. And that's the bottom line.

~faith,

Timothy.

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