Review of Statistical Analysis Concepts

 

 

We know of testing as a form of evaluation, assessment, or measurement.  As we research the subject further, we find that there are many types of tests, or methods of measurement, that can be used. 

Of paramount concern for an investigator is deciding what method to use which will provide reliable and valid data.  There are several methods available depending upon the research question to be answered. 

Whichever test is chosen for behavior assessment—i.e. data collection, it must be able to specifically serve a purpose as well as accurately differentiate between variables such as intelligence, affection, emotion, and activity.  While useful in placement and selection, tests will help the investigator determine the outcome of the experiment while also contributing input for evaluation of the program outcome. 

Among questions that should be asked when determining which type of test administer would be “is the assessed behavior physical, social or cognitive?” or “will their behavior be observed by trained data collectors or be self-reported through methods such as questionnaires, or will there be interviews?”, “is there a time limit?”, “is it subjective or objective?”, “individual or group?”, and “will the questions be multiple choice or open-ended?” 

Different types of tests that can be used are Achievement tests, Standardized tests, Researcher/Teacher-made tests, Norm-referenced tests, and Criterion-based tests. 

Multiple choice tests can be use to assess most areas.  They are easy to use for the participants and easy to score by the researchers.  A well-written test will provide accurate results.  Ill-advised situations for using these types of test would be when there is a broad content of information to be assessed or if participant writing skills are to be part of the evaluation process.  Perhaps one of the greatest advantages of using a multiple-choice test is that it positively differentiates between those who know and do not know the material being presented.  Item analysis is used to differentiate the difficulty level as well as the discrimination level.  The Difficulty index is a measure of the proportion of examinees who answered the item correctly.  It is also referred to as the p-value.  Discrimination index refers to how well an assessment differentiates between high and low scorers.

As achievement tests are likely to be used most often, Attitude tests are used to assess a person’s opinion regarding an object, individual, or event.  Two popular achievement tests are the Thurstone scale test, or method of equal-appearing intervals, which is an attitude scale consisting of items in the form of statements with which the respondent has either to agree or disagree. The second is the Likert scale test, also known as the method of summated ratings, which is an attitude scaling method in which respondents indicate the extent of their agreement with each item on a, say, five or seven point scale.  Their score on the scale is the sum of the scores for each item.  The latter is easy to develop and considered the most widely used.

When necessary to assess individual behavior patterns, two types of Personality tests are used: Projective and Structured.

As the methods discussed thus far have the participants acting as the active agents, there is another data collection method where the investigator becomes the active agent: Observation.  Different techniques used to recorder participants’ behavior include duration, frequency, interval, and continuous.  Each has their own purpose and come with their merits and possible drawbacks.  However whichever technique is used, it is imperative to remain clear of the behavior that is being recorded in order to minimize interference with the participants. 

Questionnaires also have a rightful place in data collection for many reasons.  They can be used to survey a broad geographical area and, in comparison to interviews, are inexpensive and can yield more truthful answers due to the anonymity involved.  Questionnaires, to be effective, come with the burden that they can be cumbersome and time-consuming to develop.  But as long as the basic assumptions and a systematic format are used during development, it can be an invaluable tool for collecting data.

An accompanying professional cover letter from the researcher(s) and academic sources such as professors, advisors, or institutions will show credibility to participants when soliciting their help for the study.

 Next, the process of data collection is an important process that, when planned and exercised correctly, will ease the investigator’s task during later stages.  It is systematic process that involves four steps: Construction of the data form, designation of the coding strategy, collection of the actual data, and entry onto the data collection form.

As data collection can be the most time-consuming part of the research process, Salkind (2012) has assembled his Ten Commandments of Data Collection which serve as detailed guidelines to ensure quality data collection methods as well as avoid potential errors during the process.

Once the data has been gathered, it must be analyzed.  For this, the researcher(s) should have a solid understanding of statistics.  Two basic types of statistics must be understood: descriptive and inferential. 

Descriptive statistics quantitatively describe the basic features of a collection of information (i.e. the data).  There are several terms in descriptive statistics that must be thoroughly understood and appreciated.  For this, it is most likely that most researchers would have been educated in at least a basic university-level statistics course.  Terms that require a demonstrated understanding include distribution of scores and measures of central tendency.  Measures of central tendency contain a further subset of terms such as mean, median, and mode.  Researchers must not only be intimate with these measures and the understanding of them, but must be well-versed in knowing when to use each one.

There are also measures of variability that must be understood.  Variability refers to the extent to which data points differ from each other.  There are four commonly used measures of variability: range, mean, variance and standard deviation.  In addition to these terms, an understanding is required of concepts such as the normal curve.  Also known as the bell-shaped curve, this curve plotted on a graph represents how variables are distributed.  Also involved are standard scores.  These scores, that have both the same reference point and standard deviation, are also referred to as z scores.  These z scores are necessary for the comparison of raw scores from various distributions while representing a particular location along the X-axis of a graph.

Equally important to descriptive statistics is the intimate understanding of inferential statistics.  Inferential statistics allow the researcher to use data samples to make decisions about the populations from which the samples were taken.  As earlier mentioned, this demonstrates the importance of the collected data sample accurately representing the population. 

In inference, chance plays a noteworthy role.  Chance is defined as “the occurrence of variability which cannot be accounted for by any of the variables that you are studying.”  Another key attribute to inference is the central limit theorem which states that the means of all samples selected from the population will be normally distributed regardless of the shape of the distribution—whether it is normal or not.  However for this theorem to be successful, the sample size must be greater than 30.  Because the process of sampling in not perfect, the process of sampling error is introduced.

Another important part of inferential statistics is statistical significance—also known as Type I error.  This is described as the degree of risk that the researchers are willing to take to reject a null hypothesis when it is true.  The level of significance, also known as alpha, is the risk in making this type of error. 

There are many different situations applying statistical tests.  Examples include noting average differences between two groups when measurements in the two groups are unrelated (i.e. independent).  Statistical tests can also be applied to groups that are not independent—such as a group of pilots, etc.  The tests would simply be administered at different times to note changes.

There are also techniques for working with more than one variable such as multivariate analysis of variance (MANOVA).    MANOVA takes into account the relationship between the dependent variables.  This advanced technique resembles a series of simpler statistical tests for independent means called t-tests. 

Another technique that can be used is called factor analysis.  This is also an advanced technique that allows the researchers to reduce the number of variables that are representative of a group and then use factor scores as dependent variables.

Lastly, there is a statistical technique known as meta-analysis that is used to combine, condense and simplify the findings from several independent studies on the same topic that used the same dependent variable.  This is an excellent tool to establish statistical significance with studies that have conflicting results.

Reference

Salkind, N.J. (2012). Exploring Research (8th ed.).  Upper Saddle River, NJ: Pearson/Prentice Hall.

Interpol and Human Trafficking

The International Criminal Police Organization, also known as Interpol, is an intergovernmental organization that comprises 195 members countries. Interpol helps police in all member countries work together to fight crimes and make the world safer. The organization allows police around the globe to share and access criminal data, and it offers technical and operational support. For instance, the General Secretariat of Interpol, which is run by the secretary-general, is staffed by police and civilians who coordinate Interpol activities. Through the General Secretariat, Interpol manages 19 police databases with information about criminals and crimes, including corruption, maritime crimes, terrorism, war crimes, and human trafficking.

Human trafficking, a multi-billion-dollar international organized crime, uses coercion or deception to market people between countries and regions. Human trafficking is linked to several other crimes, including cybercrime, fraudulent travel documents, and money laundering. Once the victims arrive at a destination, they are deprived of their freedom of choice and movement and frequently forced to work in precarious circumstances. Human trafficking victims may also suffer mental and physical abuse.

According to the Interpol website, several forms of human trafficking exist. One of the most widespread is forced labor. Victims are recruited mainly from developing countries by criminals using coercion and deception. Victims may be held in slavery for domestic servitude; mining, agricultural, fishing, construction, or other labor-intensive jobs. Another type of trafficking is for illegal activities, where criminals force victims to practice illicit activities and reap the profits without the risks. Some of these activities include selling counterfeit goods, stealing, and selling drugs.

The most prevalent form of human trafficking is sexual exploitation, which affects every region of the world. Vulnerable women and children are lured by promises of employment and travel to what they believe to be better lives. But when they arrive, they find themselves forced into sexual exploitation. Victims typically are provided false travel documents and held in inhumane conditions.

Human trafficking also supplies the black market with human organs. Criminals engaged in this activity exploit the desperation of patients waiting for organ transplants, which takes a long time in many countries. In addition, organ removal operations typically are carried out in secret, clandestine conditions, which puts victims' lives at risk. According to Interpol, this crime may become even more lucrative as the population ages and diabetes increases in developed countries.

Interpol seeks to give police in its member countries the tools and intelligence to investigate and deal with human trafficking. This goal is achieved by sharing the latest victim interview and investigation techniques with officers; by working across sectors to enhance the identification, reporting, and investigation of trafficking; by connecting experts from all over the world in events and conferences, and more.

Children, who are more vulnerable to trafficking, can be easily manipulated and may not realize they are victims of a crime. Interpol highlights the crucial role that social services, non-governmental organizations, and child protection units play in avoiding this trafficking. Additionally, Interpol regularly engages these institutions in some of its activities to ensure children receive adequate care and attention during operations and investigations.

PAMA Membership Categories and Benefits

The Professional Aviation Maintenance Association (PAMA) is a society of aviation maintenance technicians and businesses established in 1972. PAMA promotes industry professionalism and recognition by providing education, representation, and communication resources to its members and supporting ongoing improvement in aviation safety.

Several membership categories are available for individuals, companies, and schools interested in becoming PAMA members. The regular membership is for individuals who hold a Federal Communications Commission General Radio and Telephone certificate; those who are certified under the Mechanics or Repairman subparts of the Federal Aviation Administration (FAA) Title 14 Code of Federal Regulations (CFR) part 65; or those in an international aviation authority equivalent. Regular members can vote and are eligible to serve as directors or officers of PAMA.

Associate membership is for individuals actively engaged in aviation, such as drone operators and consultants. Associate members also have voting rights and can serve in leadership positions in PAMA. Companies actively engaged in aviation can join the PAMA company member’s community. Company memberships include one regular membership for a primary corporate representative, who may serve as a PAMA director or officer and have one vote.

Students enrolled in an avionics program, an FAA 14 CFR Part 147 airframe and powerplant program, or participating in an internship or apprenticeship are eligible for student membership. Institutions holding an FAA 14 CFR Part 147 certificate can join PAMA with an educational membership. This is a membership for one primary school representative who can serve as a director or officer of PAMA. Member schools also receive one vote.

Lastly, PAMA has a military membership for active armed forces members with experience in aviation maintenance. Similar to regular members, military members have voting rights.

Through their memberships, PAMA members recognize the excellence of aviation maintenance technicians. Members enjoy benefits in education, career development, communication, and representation. For instance, members are recognized on the PAMA website and can access the member directory to network with other members.

Moreover, members receive the weekly PAMA MX News Watch to stay current on industry news and events, as well as considerable discounts on job postings at JSfirm.com. Other benefits for PAMA members include lower rates for a law firm specializing in aviation law, discounted Dell products, and over 80 hours of on-demand training by the Aeronautical Repair Station Association. Additionally, employees of PAMA’s corporate members receive 10 percent off the associate or regular membership.

PAMA gives awards and scholarships to current and future professionals in the aviation maintenance industry. In addition, awards are offered to legal US residents who have recently graduated or are enrolled in an FAA part 147 school. Applicants who are members of PAMA have a better chance of receiving scholarships. One scholarship is the ​JSFirm.com Aviation Mechanic Student Award. Monetary awards can be used to pay for tuition, purchase tools, or for other education-related expenses.

Aviation Safety Management Systems

Safety management refers to the application of a set of principles, frameworks, measures, and processes to prevent injuries, accidents, and other negative consequences that the usage of a product or service might cause. According to the Federal Aviation Administration (FAA), having a safety management system (SMS) is mandatory and forms an integral part of an air carrier’s certification. In recent years, the technology used in aviation safety management systems has evolved.

Safety management systems aim to help air carriers comply with regulatory requirements created by different global agencies. In response to the need for better safety, agencies like the International Air Transport Association (IATA), International Civil Aviation Organization, and FAA continually seek to improve safety regulations. Many organizations and air carriers have incorporated the safety requirements set by these regulations into their SMS.

Aviation organizations are using the latest IATA Operational Safety Audit programs or Air Transportation Oversight System checklists. Organizations are also updating their documentation and procedures as per the latest FAA guidelines. With the evolution of safety management systems, organizations and carriers can now directly gather vital "feeds" from the updated regulatory requirements in real time. This facilitates the ability to respond to changes in regulations and rules faster and keep safety management systems current.

Risk management is critical for improving aviation safety. In the traditional risk management model, the reliance was on historical data. However, with airlines, the availability of historical data cannot be relied upon to shape risk management, as incidences (accidents) are few. Thus there is a shortage of data to formulate or project a good risk picture. The bow tie model suits the needs of the industry in this regard.

The bow tie model is a well-thought-out approach to risk management and identification that focuses on causal linkages between sources, or factors leading to an event, and consequences (risk) and controls. Organizations are employing the bowtie methodology to derive preventive and control measures by examining the potential causes and risks linked to a particular occurrence. The model is also becoming increasingly common when planning for unforeseen risks.

The aviation industry continues to evolve and innovate. A notable development has been the increasing uptake of digital technology and composite materials in aircraft design and building. Many of these emerging technologies have boosted aviation safety management systems through better cockpit instrumentation displays and the use of computers in fly-by-wire systems.

However, technology adoption has also come with an increased potential for creating unanticipated outcomes and consequences. Previously, pilots had minimal data at hand to guide their actions and relied on their instruments to steer a craft. Today, on the other hand, the sheer amount of information available to a pilot can be overwhelming. While modern “glass cockpit” technology has improved visual awareness for pilots, several concerns have been raised.

The 2009 loss of Air France flight 447, which was carrying 228 people, is a case in point. Investigations into the accident concluded that the crew got confused by the instrumentation, leading to inappropriate action when the plane encountered turbulence over the Atlantic Ocean during a thunderstorm. The 2013 Asiana crash also raised concerns over pilots’ reliance on automation.