Search Engine Advertising Essay Example | Topics and Well Written Essays - 1000 words

Search Engine Advertising - Essay Example Written language is a powerful tool for expressing ideas and feelings when used correctly and to the right audience. The ambiguity of spoken word is one of the reasons behind the development of text theory. The main aim of text theory is to engrave systems of unambiguous rules which put across the association between connotation and text in various languages. Text theory, therefore, seeks to ensure that written word is free of ambiguity and well understood by the audience. Online advertising relies majorly on the written word. It is therefore important to ensure that these advertisements are rational especially to the persons who will be privileged to read them. Companies should, therefore, take the keen interest in the text that conveys advertisement message on the internet (Hollis 2005). Question two Affiliate programs refer to planning between an online merchant website and associated web sites that enable the later to accept traffic from the merchant web sites for a fee. Links are normally posted by the associated websites and payments are made depending on agreed terms and conditions. In most cases, the contract is based on factors such as the number of persons the associate web site transfers to the merchant site. Other agreements may involve payments depending on the number of persons that pay a visit to the web page that has the merchant website advertisement poster. This is fundamental especially for upcoming companies that want to grow the business at a faster rate.... This is fundamental especially for upcoming companies that want to grow business at a faster rate. Written language is a powerful tool for expressing ideas and feelings when used correctly and to the right audience. Ambiguity of spoken word is one of the reasons behind the development of text theory. The main aim of text theory is to engrave systems of unambiguous rules which put across the association between connotation and text in various languages. Text theory therefore seeks to ensure that written word is free of ambiguity and well understood by the audience. Online advertising relies majorly on the written word. It is therefore important to ensure that these advertisements are rational especially to the persons who will be privileged to read them. Companies should therefore take keen interest on the text that conveys advertisement message on the internet (Hollis 2005). Question two Affiliate programs refers to planning between an online merchant website and associate web sites that enables the later to accept traffic from the merchant web sites for a fee. Links are normally posted by the associate websites and payments are made depending on agreed terms and conditions. In most cases the contract is based on factors such as the number of persons the associate web site transfers to the merchant site. Other agreements may involve payments depending on the number of persons that pay a visit to the web page that has the merchant website advertisement poster. Ideally, when a hyperlink on an associate website earns the merchant site finance or popularity, it is the duty of the merchant site to make payments to the associate site as pertains to the contract (Evans 2009). Three parties are in most cases involved in an

Studying abroad Essay Example | Topics and Well Written Essays - 500 words - 1

Studying abroad - Essay Example Problems encountered by international students should be given attention and solutions to help foreigners cope with their new environment and perform well in their studies. This paper will discuss some of these problems such as homesickness and the multi-cultural experiences of international students. Perhaps the most common complaint among foreign students is homesickness. Studies show that â€Å"students in America experience homesickness due to culture shock† (Harrison and Brower). The culture in America is definitely different from most foreign students especially those coming from eastern countries. It is not just the language that is different but the divergences in food, clothing, customs and practices are also quite astonishing to foreign students. This makes them long for familiar environments and people they have been used to. From the studies of Harrison and Brower, this separation anxiety has a strong correlation to psychological hardiness- â€Å"a personality variable that seemingly impact students’ adjustment to their often challenging and bewildering host cultures† (Harrison and Bower). The research of the shows that those who are able to adjust and actively involve themselves in whatever challenges individuals are faced with, experience less h omesickness. In addition, those who are able to act strong and able in their new environment are less stressed and therefore are able to cope with the demands of their host culture. Those who are resilient to changes are also found to be stronger in times of emotional and psychological troubles among foreign students. In contrast to the negative effect of foreign studies, there is also a great advantage especially with those who have strong psychological hardiness and are open to challenging experiences. According to Christine Lee, David Therriault and Tracy Linderholm, â€Å"multicultural experiences such as studying abroad are quantitatively and qualitatively

Diabetes type 2 Essay Example | Topics and Well Written Essays - 500 words

Diabetes type 2 - Essay Example inactivity, fat distribution (excess fat in the abdomen), age (above 45 years), race (African Americans, Asian Americans and Latinos among other natives), pregnancy and prediabetes (higher than normal blood sugar level). This paper will discuss two treatment methods of diabetes type 2 and the professionals involved in these treatments. With over 2.9 million of UK population being diagnosed with diabetes, and there being no cure for diabetes, an effective treatment plan is necessary and which should be followed. The two common methods of treatment of this disease are monitoring the blood sugar level and using medication. The first treatment method is the use of medication. This treatment method is mainly for those who cannot maintain a reduced blood sugar level or their condition has advanced. Some of the diabetes medications prescribed includes metformin (which is aimed at lowering production of glucose in the liver), glipizide (aimed at stimulating the pancreas to release more insulin) or acarbose (that prevents enzymes from breaking down carbohydrates in the intestines). Other than these medications, there is also insulin therapy which is administered through injection and its advantages is that it works rapidly and lasts longer (Spencer and Hughes, 2005). Monitoring of the blood sugar level requires a change in the lifestyle (as some of the risk factors are associated with lifestyle). This will require the diabetes patient to constantly exercise to burn off excessive weight around the abdomen area and in order to also reduce weight generally for those considered obese when a BMI (body mass index) is conducted. Healthy eating is also required which means eating foods high in fibre like whole grains, plenty of fruits and vegetables. A reduction in the intake of carbohydrates, sweets and animal products in general is also one of the treatment plans. It is also important to lay off stress or factors causing or perpetuating stress as well as reducing alcohol

The 14 Points Plan by Woodrow Wilson Essay Example | Topics and Well Written Essays - 2000 words

The 14 Points Plan by Woodrow Wilson - Essay Example However Treaty of Versailles had little connection with these fourteen points and was not ratified by the US senate. On October 16, 1918, an interview was conducted by President Woodrow Wilson and William Wiseman. This interview was the basis of acceptance of these fourteen points by German Government. A negotiation report was also made on these fourteen points. These fourteen points were also accepted by Italy and France. After the session Britain signed acceptance to all the points except freedom of sea due to the condition of allies. These fourteen points are based on the research of inquiry. This speech included many principles of progressivism which promoted domestic reforms in US and translated then into foreign policy (Mulder, 71). This fourteen point speech is the only statement which aims to focus on wars as compared to any other nation fighting in World War I. Some nations tried to give indicators in relation to their aims, but majority of nations tried to keep their war go als private. This speech also reacted to Vladimir Lenin’s Decree on Peace in October 1917; in it Russia made an immediate proposal of withdrawal of war and promotes peace and freedom, which was further compromised by territorial annexations. 1.2 Fourteen points.The first five points of fourteen points focuses on international concerns, while the others refer to territorial questions.†¢Open diplomacy.There should be open peace in the nations, which means there should not be any private international understanding among nations. Open diplomacy should be promoted in order to be frank with the citizens and to understand public views. Freedom of the seas There should be absolute freedom to navigate on seas and territorial waters. It should be available in both the cases i.e. wars and peace. However, while enforcing international covenants it can be closed wholly or partly. But this can be done only in case of international actions and practices. Removal of economic barriers A ll economic barriers should be removed and a sense of equality should be created among all nations. There should be peace among all nations. Reduction of armaments National ornaments should be greatly reduced in order to ensure domestic safety in the nations. A guarantee should be given for the reduction of armaments. Adjustment of colonial claims There should be enhancement of open minded and free adjustment of colonial claims. It should strictly follow the principle of identifying sovereignty in relation to the interest of citizens. People should be given equal weight age with the colonial claims of government. Conquered territories in Russia There should be a migration in Russian territory. All issues affecting Russia must be resolved, so that they can work on the basis of cooperation with other nations of the world. This will create an unrestricted and blatant opportunity for the nation in order to be independent. It should be able to identify its own national policies and polit ical developments. Russia should be invited to enter as a free nation, making its own choices and beliefs. In spite of invitation, all kind of assistance should be given to this nation in order to fulfill its desires and needs. This help if given to Russia, will lead to test the nations goodwill and understanding their needs. It will differ from the

Campare Sonnet Essay Example for Free

Campare Sonnet Essay Shall I compare you to a summers day? Thou art more lovely and more temperate:| You are more lovely and more constant:| Rough winds do shake the darling buds of May,| Rough winds shake the beloved buds of May| And summers lease hath all too short a date: | And summer is far too short:| Sometime too hot the eye of heaven shines,| At times the sun is too hot,| And often is his gold complexion dimmd; | Or often goes behind the clouds;| And every fair from fair sometime declines,| And everything beautiful sometime will lose its beauty, By chance or natures changing course untrimmd;| By misfortune or by natures planned out course. But thy eternal summer shall not fade | But your youth shall not fade,| Nor lose possession of that fair thou owest;| Nor will you lose the beauty that you possess;| Nor shall Death brag thou wanderst in his shade,| Nor will death claim you for his own,| When in eternal lines to time thou growest:| Because in my eternal verse you will live forever. | So long as men can breathe or eyes can see,| So long as there are people on this earth,| So long lives this and this gives life to thee. So long will this poem live on, making you immortal| My mistress eyes are nothing like the sun;| My mistresss eyes are nothing like the sun;| Coral is far more red than her lips red;| Coral is far more red than her lips;| If snow be white, why then her breasts are dun; | If snow is white, then her breasts are a brownish gray;| If hairs be wires, black wires grow on her head. | If hairs are like wires, hers are black and not golden. I have seen roses damaskd, red and white,| I have seen damask roses, re d and white [streaked],| But no such roses see I in her cheeks; | But I do not see such colors in her cheeks;| And in some perfumes is there more delight | And some perfumes give more delight| Than in the breath that from my mistress reeks. | Than the horrid breath of my mistress. | I love to hear her speak, yet well I know | I love to hear her speak, but I know| That music hath a far more pleasing sound;| That music has a more pleasing sound. I grant I never saw a goddess go;| Ive never seen a goddess walk;| My mistress, when she walks, treads on the ground:| But I know that my mistress walks only on the ground. | And yet, by heaven, I think my love as rare | And yet I think my love as rare| As any she belied with false compare. | As any woman who has been misrepresented by | The sonnet 18 is a Shakespeare’s early love poem which is about affection of a young man to his beloved. It starts with the genuine question, â€Å"shall I compare thee to a summer’s day? † The speaker is thinking about his lover’s beauty rather than putting her poem in a conventional love poem formula. Then, he points out her lover’s beauty was more beautiful and constant than a summer day; her beauty was eternal and would be preserved in the lines of this poem. However, Sonnet 130 is a more convincing love poem because it is more descriptive and realistic in depicting his lover which shows that his love is more sincere and everlasting. Sonnet 18 is about the feeling of perfection of his lover’s beauty while sonnet 130 is about the real appearances of her mistress. In sonnet 18 the speaker says, â€Å"Shall I compare thee to a summers day? Thou art more lovely and more temperate:† Although summer is pleasant season, the speaker never talks about how his lover is like a summer day nor how she was more lovely. He did not give life to his lover because we can use this poem to mostly every woman in the world; he does not specifically describe his lover. In sonnet 130, the speaker explicit states what his mistress looks like. The speaker says, â€Å"My mistress eyes are nothing like the sun;/Coral is far more red than her lips red;/If snow be white, why then her breasts are dun; /If hairs be wires, black wires grow on her head. It explicitly describes his lover in an honest way. Although love poems often use sun, snow and beautiful objects to praise the beauty of their subject, realistic love is not about an idealized sense of beauty. A person cannot love another one simply because they are physically beautiful. We think that the women with red lips, white skin and gold hair are beautiful, but does it mean the women that having â€Å"not so† red lips, brownish skin, and black hair are not beautiful? Beauty is subjective. When people love someone, they would define beauty by his/her st andard. By describing in detail of his lover’s appearance, the speaker of sonnet 130 really know his lover. Love is not only about the feeling of a warm sunny summer day, but know a person as a distinguish individual. Sonnet 130 make his lover feel special and superior because the speaker pay quite attention to her actual appearance, and honestly writes it down in a poem. It also gives her the sense of security because she knows he loves her for who she is and she does not need to pretend to be a perfect figure nor be an everlasting summer day. Sonnet 130 ses reality to prove the speakers love while sonnet 18 uses exaggeration. Sonnet 18 illustrates only the speaker’s love for his beloved’s beauty while in sonnet 130 illustrates more sincere love for her mistress even though she is not perfect. In sonnet 18, the speaker claim his lover was eternal by saying, â€Å"By chance or natures changing course untrimmd;/But thy eternal summer shall not fade /Nor lose possession o f that fair thou owest;/ Nor shall Death brag thou wanderst in his shade,† The speaker praise that her beauty stronger than the nature. Although the speaker values her beauty greatly and even believed her is beauty has the power to overturn the nature, it is only his wish and imagination that her beauty would not change. It will not be convincing to a woman since they consciously know that appearance will change. His lover will feel that the speaker only focuses on her beauty, but not anything else. In sonnet 130, the speaker states, â€Å"I love to hear her speak†. The speaker loves her thinking, her opinions and her intellects. The speaker values her thought which is not very common even in current society. Relationship is about equality and respect. Many men treat women as an object that has nothing inside. Even in sonnet 18, the speaker compares his lover as an eternal summer which also an object. Then, the speaker says, â€Å"I grant I never saw a goddess go;/My mistress, when she walks, treads on the ground:† . The speaker wants to compare his mistress with a goddess as many sonnets do, but he admits that he never saw one. It mocks that other poets are dishonest which compare their lover to a figure they never see. He emphasized the word â€Å"my mistress† which shows that he takes pride that this woman is his mistress as while as the ways his mistress is like. He shows that this poem is about her mistress but not anybody else, not even goddess can compare with his mistress. He cares only his mistress which makes her even superior to a goddess. He shows that although her mistress is not an immortal figure, but her mistress is special for him. Then, speaker of sonnet 130 transits his understanding of her mistress to his confession of love while in sonnet 18, the speaker transits his lover’s beauty to mortality. The speaker of sonnet 18 uses poetry to eternalize his lover while in sonnet 130, the speaker shows that his love for her is eternal. In the end of sonnet 18, the speaker says, â€Å"So long as men can breathe or eyes can see, /So long lives this and this gives life to thee†. The life of the subject will be an endless summer, but only because the speaker has immortalized her in this poem, and only if people continue to read these verses. It makes the readers feel that the poem itself is greater than the subject. The poem builds up this subject with eternal beauty and the subject only lives in the poem. However, this poem is for a living woman, and she is not living by her beauty or by the poem. Every woman knows this poem cannot real give immorality to them because the readers do not even know who the subject is. Not only the woman reading this poem cannot relate herself to this poem, buy she also will feel the speaker’s love is unrealistic and superficial and will not last long. In contract, in sonnet 130, the speaker claims that â€Å"And yet, by heaven, I think my love as rare†. His claim is convincing because in previous lines, he honestly depict his mistress and we expect he is honest when he says that he loves her. Furthermore, if his love for her is not because she is idealized beautiful since she is not, then he must love her because of her which we define as true love. His love would not fate with changing of appearance or time. His mistress would feel that she has the speaker’s heart forever. Sonnet 130 well proved the speaker’s love for her mistress; his love is about understanding and respect; his love is strong and everlasting. In contrast, sonnet 18 is more about the speaker’s passion to his lover’s beauty than his love for her as a whole individual. Many people say romantic love would last long. It is because that when people know each other well, their flaws would appear, and they are intolerance to these flaws. They would try everything to change each other to the way they want, but they most likely fail. Everyone is difference and not perfect, so when people love someone, they should acceptance their flaws.

Symbolism in Hills Like White Elephants Essay Example for Free

Symbolism in Hills Like White Elephants Essay Difficulty and dealing with difficulty are part of the balance that makes up the human experience. Forced to deal on one side with the selfishness of other people and on the other side by a terrible fear of what they do not know, there are two characters in Ernest Hemmingway’s 1927 story, Hills Like White Elephants. Here, the story shows us a man and woman who are overcome by the personal things they are dealing with. In order to deal with them, though, these characters are behaving in a very detached way that seems somewhat defensive against these things. In the female character, named Jig, Hemmingway shows a woman who is ripe for experiences with symbolic meaning. Implied throughout the story is the unspoken idea of a pregnancy. The man aggressively tries to manipulate Jig into having an abortion without ever saying it out loud. This is the issue that beings to become more clear to the reader as the couple talks. They speak with anger and bitterness, and the reader can feel that there is a sense of something bad coming in the future. This is the feeling which is shown through Jig, who makes a statement with importance at the start of the story. She looks at the two white hills showing in the distance with a barren brown piece of land in front of the them. She says that â€Å"they look like white elephants. † (1) The angry conversation that comes afterwards between the two characters shows how they both respond differently to the simile. The woman seems to view the hills with some kind of wonder and even with the consideration that they are of a fantastic nature. This is especially true by the way they were so different looking from the brown earth around them. For the man, the hills and the simile that his partner states make the man a little hostile. He is defensive in a way that says he is afraid or resentful. To him, the objects in the distances look like a challenge. This shows how he views the unknown. Another symbolic way to look at the hills is to see them as symbolic of motherhood or of pregnancy. This pair of hills can be seen as the swollen breasts of a pregnant woman. And with the brown land in front of them, they look fertile in a place that mostly cannot support life. This is a metaphor for the life of the woman in the company of this selfish man. The dry and unforgiving way that the man talks to Jig helps to show why her life has this negative quality. In a very difficult discussion where the couple speaks with sarcasm and dislike, the are detached and argumentative. This shows the unhappiness of the human condition and how they try to hide from themselves and each other. The conversation they have seems like it’s supposed to help them be distracted from their pain the consequences of their lives. Specifically, when the woman says that â€Å"Thats all we do, isnt it look at things and try new drinks,† she shows how directionless she feels her life has become. (1) Even in the middle of a horrible decision like that of having an abortion, the woman tries to dismiss the importance of her own existence. The symbolic relationship between the hills, the matter of the woman’s pregnancy and the overall unhappiness felt over it make a short story that doesn’t state much deeply meaningful anyway. If on the surface the characters battle with each other in a way to hide from their own feelings, they still share the fear of the unknown that is now in their careless lives. Shadowing all of this exchange is the image of the hills and the negative promise which they seem to promise is waiting on the horizon for the tired and unhappy couple.

confounding factor or lurking variable

confounding factor or lurking variable Confounding variable, also known as confounding factor or lurking variable can be defined as an undesirable variable that has an influence on the relationship between the variables of an experiment. Although they are not the variable of actual interest (i.e. the independent variable), they can influence the outcome of an experiment and they are considered to be undesirable as they could add error to an experiment. A proper designed experiment should aim to decrease or control the influence of such confounding variables in order to avoid type 1 error; an error that raises a false positive conclusion that the independent variables have a casual relationship with the dependent variable. The relationship between the two observed variables is called a spurious relationship, hence a confounding variable is a threat to the validity of inferences made about cause and effect, i.e. the internal validity because the observed effect should be attributed to the independent variable rather than to the confounding variable. An example can be illustrated by the relationship between ice cream sales and drowning deaths. When these variables are entered into a statistical analysis, they may show a positive and potentially statistically significant correlation. However, it is a mistake to infer a causal relationship (i.e., ice cream causes drowning) because an important confounding variable which causes both ice cream sales and an increase in drowning deaths has not been accounted for: i.e. summertime. Although there is a body of literature of criteria for causality, Pearl claimed that confounding variables cannot be defined in terms of statistical notions alone; some causal assumptions are sometimes necessary. For example, when causal assumptions are being defined in the form of causal graphs, a simple criterion called backdoor will identify sets of confounding variables. Types of confounding variables Confounding variables may also be categorized according to their source: the choice of measurement instrument, situational characteristics, or inter-individual differences. Solution There are several ways to combat confounding variables in an experimental design by excluding or controlling it. Here is the following: Case control studies: by assigning the same confounding variables to both the experimental and control group can control for such confounder, for example, if the cause of multiple infarct dementia is being studied, age and sex could be the confounding variables, therefore these factors should be matched paired between the two participant groups. In addition, randomization is also another solution as having all confounding variables (whether known or unknown) will be equally distributed across all groups. Cohort studies: this is done by admitting a specific group of participants into the sampling population, for example a specific age range that may affect multiple infarct dementia, therefore only a certain group is chosen for the study design such as male aged 45-50 years old. This would limit the degree of matching between the groups and also cohorts can be comparable in regard to the possible confounding variable. Stratification: in the example of multiple infarct dementia study, physical activity is hypothesized to be a variable that can prevent this dementia from happening. With age as a possible confounder. The sampling data will then be stratified by age group so that the association between physical activity and dementia can be analyzed per age group. If different age group yields different risk ratios (this can be analyzed by statistical tools called Mantel-Haenszel methods), then age is seen as a confounding variable. Despite solutions for the controlling and limiting confounding variables, these strategies have limitations too. For example if a participant in the case-control study is a 47year old African-American from Alaska, avid tennis player, vegetarian, working as an engineer and suffer from multiple infarct dementia. Proper matching would require a person of the same characteristics but with the sole difference of being healthy. This is extremely difficult to achieve and there is a risk of over- or undermatching of the study population. Additionally, in a cohort study, too many people may be excluded with this criteria, and in stratification, single strata can get too narrow and contain only a small, non-significant number of samples. Randomization One of the most common reasons for the existence of confounding variable is when the experimental design does not randomly assign participants to groups or some types of individual difference such as ability, extroversion, height and weight. For example, studies involving a comparison between men and women are inherently plagued with confounding variables since the social environment for males and females is very different to start with. However, this does not mean that there is no value in gender comparison studies or other studies that does not employ random assignment but it implies that results interpretation should be done cautiously. In sum, random assignment is a useful and powerful tool in experimental design. Although it does not minimize the overall amount of extraneous variable in an experiment, it aims to equalize the error that may occur as a result of extraneous variable, therefore it can greatly decrease systematic error: error that varies within the independent variab le. Multivariate analyses Another method for controlling confounding variable is by the use of covariates in multivariate analyses. However, this only gives little information about the strength of the confounding variable compared to stratification methods. Furthermore, confounding variables are not always known or measurable which means residual confounding (term for incompletely controlled confounding) may appear. In an experimental design, covariate adjustment can help to reduce the noise in an outcome variation whilst enabling the manipulation effect to be performed. In sum, successful randomization can minimize confounding variables by bother measured and unmeasured factors, whereas statistical control addresses only confounding variables that have been measured and can introduce more confounding variables and other biases through inappropriate control. Mismeasurement and mis-specification Although it is important to spot confounding variables in a study there is often a risk of having a statistically controlled but imperfectly measured factor that may confound an association of the variables. This is termed residual confounding which describes the mismeasurement and an example is given to illustrate this. In a study example, it was found that people with higher rate of vacation is correlated with lower risk of mortality. Several explanations can account for this as vacation mitigates stress, diminishes anger and encourage more exercise. On the other hand, healthier people might be more likely to travel so vacation may not be a genuine causal factor but only a marker of initial health status that naturally predicts longevity. Consequently, vacation may remain to be a significant predictor even after adjusting for baseline health status as the covariate. It is therefore easy to construct a series of potential confounders but many would lack plausibility. For example, pe ople with more friends may have more vacations and friend was indeed the predictor variable instead, low-stress working environment and wide range of food (I.e. completeness of diet) may all attribute to prolong life too. However, because plausibility is a highly subjective factor for considering whether enough potential founders are included. To identify confounders Priori knowledge of the likely causal pathways are required. The major drawback of this is that observational studies imply that the strength of any causal inference will depend on the biologic plausibility of the putative factor, and the implausibility of uncontrolled potential confounders. In addition, observations contain some judgmental component which varies from experimenters. For example, vacation may prolong longevity because sick people tend to travel less, to deal with this. Measurements of participants initial health may be used as an adjustment but this however cannot be assessed without error. Moreover, hea lth can be measured in so many different ways and not all can be included and controlled for. This raises more and more questions such as: can the use of initial stress test be used to capture aspects of health confounded by vacation? Is body mass index relevant? Consequently, even if the optimal measure of confounder is used it is measured with error and adjustment for it may not eliminate the effects of vacations. From the statistical analysis perspective, poorly measured confounding variables causes more problems as its effect may not be linear, by assuming linearity on the outcome as specified by the model by entering confounding variables as a covariate in standard regression models may not fully adjust for the confounder effects are not linear on that scale. Mediators and confounders There is a common conflict that different causal explanations can be possible when adjustment is used to reduce or eliminate the predictive power of the independent variable. For example, a confounding variable may sometimes be a marker of some causal factors but it is not directly involved in the causal chain from one variable to another and there is a problem of over-adjustment. Considering an example on the hypothesis that high blood pressure (BP) reaction to stress causes Hypertension. To test this hypothesis, a longitudinal study should be conducted where BP reactivity and resting BP levels of a large group of participants should be measured. Result findings should report that excessive reactivity to be the risk factor for later hypertension but the problem is reactivity may just be a marker for elevated BP resting level and it is not important per se. consistent with this problem, those participants with higher resting BP may correlate with high BP reactivity scores. To control for the current confounding variable, the initial resting BP levels should be adjusted by regression analysis which llustrates whether BP reactivity is attributed to any predictive information beside just the initial resting BP level. This may show that reactivity is no longer a very predictive factor and most of the variation in the follow-up BP levels may be accounted for by the initial resting levels. However, this does not mean that reactivity is not causally related to future BP status, i.e. if increased reactivity preceded initial increase in resting BP level, it could also be responsible in part for the initial increase in resting BP level. This is a situation whereby a single variable may have both confounding and mediating roles simultaneously. The example of vacation and mortality is used to illustrate this: assuming that people who go on more vacations are less likely to die over a 5-year longitudinal study, including a factor: initial health status in the regression mod el could eliminate this association. Alternatively, if people in poor health take fewer vacations then this elimination may reflect the removal of a confounding variable by health status. However, if the participants tendencies to go on vacation are constant over the 5 year period then health status will reflect the cumulative health impact of a lifetimes vacation habits. This shows that health status will contribute partly as a mediator of vacationing effects. This confusion between a mediator and a confounder will be less apparent if the risk factor is not stable over time. For example if the participant has only just started having vacations, then these will not be reflected in the initial health status and may have higher opportunity to predict subsequent health with initial health status as a covariate in the analysis. However, if these changes become out of control, it can create a quasi-experimental design. For example, if people take vacations due to change in their company policy rather than the reason of making friends or have spare time, and other group have less vacation for the same reason. Then in this case, it is possible to assess the effect of vacation independently of initial health status. In sum, indiscriminate adjustment of covariates may result in erroneous conclusions and many socialdemographic variables can be mediated by other factors such as low income, unfulfilling jobs, no friends etc. moreover, there may also be other intermediate variables like self-determinations and release of stress hormones that may affect the results. Considering the wide range of variables listed, any inaccurate measures of them may lead to a reduction or elimination of predictive power. Moreover, by controlling a mediator may produce further confounding variables, which will then increase or decrease the associations of the independent and dependent measures. Furthermore, it may even create a new spurious association when in fact no effect is present. In sum, despite the number of limitations discussed in this critical review, they have an important role in behavioural research as randomized trials are sometimes found to be impractical and unethical. In spite of the hazardous statistical control of confounding variables will gain insight into special cautions in drawing conclusions and writing research in the future.